A Complete Guide to the Novum Organum and the Great Instauration
Introduction: The Author’s Preface
We begin at the opening of the work, where Bacon addresses the reader directly to explain what he is attempting and why a radical new beginning in philosophy is necessary.
Bacon opens by declaring that the state of knowledge as he finds it is “depressed” and that nothing less than a “total reconstruction of sciences, arts, and all human knowledge” is required. He is not merely offering corrections or additions to existing systems, he writes, but “a kind of new birth” of the entire enterprise of understanding nature. The present condition of learning, he argues, is characterized by endless disputes and barren results. Men have been content to defend ancient authorities, particularly Aristotle, rather than to investigate nature directly. The result is that philosophy has become a matter of “wrangling” rather than “works” — it produces arguments but not fruit.
Bacon then distinguishes his project from all previous ones. Others have promised to reform knowledge, he says, but they have done so by adding new systems to old ones, or by attacking particular errors while leaving the foundations untouched. He intends instead to “begin entirely anew” — to lay new foundations, to clear the ground completely, and to build from the bottom up. This is the meaning of his title: the Great Instauration, a restoration or renewal, not a repair. He describes his method as one that “derives axioms from the senses and particulars, rising by a gradual and unbroken ascent, so that it arrives at the most general axioms last of all.” This is the opposite of the customary method, which leaps from particular observations to the most general principles and then forces everything to conform to them.
“My intention is to open a new way for the understanding, a way which they have never tried and which they know not, a way that consists not in the delivery of things already invented, but in the method of inventing them.”
What Bacon means by this is that he is not handing the reader a finished system of philosophy — he is handing them a tool, an instrument for making discoveries. The work he is producing is not a body of knowledge but a method for producing knowledge. This is why he calls his main work the Novum Organum, the “new instrument” — as opposed to the old Organon of Aristotle, which was a set of logical tools for debating propositions. Bacon’s new instrument is a tool for interrogating nature itself. The significance of this preface is that it sets the radical ambition and the epistemological humility of the entire project: Bacon knows that his own results may be imperfect, but he insists that the method, if properly followed, will yield ever greater results over time.
Plan of the Work
Here Bacon lays out the architecture of the Great Instauration as a whole, explaining how the various parts fit together and what each is meant to accomplish.
The Great Instauration is divided into six parts, each with a specific function. The First Part is the Partitions of the Sciences, which surveys the existing state of knowledge, catalogues what is known, and identifies what is missing. This part, Bacon says, is meant to give an overview of the territory, showing which areas of learning are well-cultivated and which lie fallow. He notes that in this part he will “set forth a partition of the sciences” that is based not on the subjects studied but on the faculties of the human mind: memory yields history, imagination yields poetry, and reason yields philosophy.
The Second Part is the Novum Organum itself — the new method for interpreting nature. This is the heart of the entire work, and Bacon warns that it is “the most difficult and important” of all the parts. Here he will present his new logic, which is not a logic of syllogisms but a logic of induction, designed to investigate the forms and causes of natural phenomena. The Third Part is the Phenomena of the Universe, which is to be a natural and experimental history — a vast collection of observations and experiments, organized not by speculation but by the requirements of the new method. Bacon insists that this history must be “collected and digested” before any sound philosophy can be built upon it.
“For the matter of which the universe is made, the matter of the heavens and the earth, is not to be confined within the narrow limits of human reason; but the human understanding must be suffered to range at large, and to take in the whole extent of nature.”
The Fourth Part is the Ladder of the Understanding, which will contain examples of the new method applied to particular cases, showing step by step how it works in practice. The Fifth Part is the Forerunners, or anticipations — provisional results obtained before the full method is complete, offered not as true philosophy but as useful temporary aids. The Sixth Part is the Philosophy itself, which will be the final, completed system of natural knowledge that the new method will eventually produce. But Bacon is honest here: he says he does not hope to see this sixth part completed in his own lifetime. His task is to provide the method and the history; the final philosophy will be the work of future generations who follow his path.
Preface to the Novum Organum
This preface, addressed specifically to the reader of the Novum Organum itself, explains the nature of the method and the opposition Bacon expects to face.
Bacon begins by stating plainly that the state of learning is excellent in matters of “civil life and the arts” but utterly deficient when it comes to “the sciences and philosophy.” He compares the existing philosophy to statues that are “beautiful to look upon but have no motion” — they are elegant but sterile. The problem, he says, is that men have committed a fundamental error: they have reversed the proper order of inquiry. Instead of beginning with experience and rising slowly to axioms, they begin with axioms and then force experience to fit them. This is the error of the anticipations of nature — hasty generalizations that anticipate what nature might be like, rather than interpretations of nature — careful readings of nature based on methodical observation.
Bacon then identifies three kinds of obstacles he expects to face. First, there are those who are deeply invested in the existing systems — the ancients who defend Aristotle and the scholastics who defend the tradition. These men, he says, “have already taken a position” and will resist any fundamental change. Second, there are the empiricists who rely on narrow experience — the alchemists and mechanics who collect facts without method and produce “a kind of rhapsody and raving.” Third, there are the skeptics who have given up on the possibility of certain knowledge. Against all three, Bacon insists that a middle path is possible: a method that respects experience but does not drown in it, that seeks certainty but does not claim to have already found it.
“We need a way which, by a certain method, may lead us from the sense and from particulars to axioms; and then again from axioms to new particulars, for the discovery and designation of new works.”
The key phrase here is “new works.” Bacon’s criterion for true knowledge is not logical consistency or beauty of argument — it is practical power. A true axiom, he says, will enable us to produce new effects in nature. This is the test: if a philosophy cannot generate new inventions, new technologies, new ways of manipulating the material world, then it is false or useless. Bacon is announcing that his method is fundamentally operative: it exists not for contemplation but for action, not for debate but for dominion over nature. The preface closes with Bacon’s admission that he is “building a foundation” and that the finished structure will be the work of many hands over many generations. He asks only that readers “judge of the way by the way” — test the method by using it, not by arguing about it in advance.
Aphorisms Concerning the Interpretation of Nature and the Kingdom of Man — Book I
This is the first major division of the Novum Organum itself, consisting of 130 aphorisms that diagnose the current state of human knowledge and clear the ground for the new method.
The first aphorism proclaims the central thesis succinctly: “Man, as the minister and interpreter of nature, does and understands as much as his observations on the order of nature permit him, and neither knows nor is able to do more.” This is the foundational claim of the entire work: human power over nature is exactly proportional to human understanding of nature. To command nature, we must obey her — we must learn her laws and work within them.
Aphorisms 1 through 37 lay out the general diagnosis. Bacon argues that the current state of knowledge is characterized by its complete failure to produce useful results. The sciences, as currently practiced, are “barren of works” and “full of controversies.” They are like virgins consecrated to God — they produce nothing. The reason, Bacon explains in aphorism 19, is that “the subtlety of nature is far beyond the subtlety of the senses and the understanding” — our ordinary mental equipment is simply not adequate to the task. We need artificial aids, instruments, and methods. Just as we use lenses to see distant stars, we need a “new organ” to see into the structure of nature.
The core of Book I is Bacon’s doctrine of the Idols — the false notions and mental habits that prevent us from seeing nature clearly. He identifies four kinds of Idols. The Idols of the Tribe (aphorisms 45-51) are those that arise from human nature itself — our tendency to see more order and regularity in things than actually exists, our susceptibility to confirmation bias, and our tendency to be swayed by the strongest impressions rather than the most subtle ones. The Idols of the Cave (aphorisms 53-58) are the particular biases of each individual — our education, our temperament, our favorite authorities, our professional deformations. Each person, Bacon says, “has a cave or den of his own” that refracts the light of nature in a distorted way.
“The Idols of the Tribe have their foundation in human nature itself, and in the tribe or race of men. For it is a false assertion that the sense of man is the measure of things. On the contrary, all perceptions as well of the sense as of the mind are according to the measure of the individual and not according to the measure of the universe.”
The Idols of the Marketplace (aphorisms 59-68) are the most troublesome because they arise from language itself. Words, Bacon argues, are imposed on things according to the common understanding of the crowd, and these words often carry meanings that have nothing to do with the realities they supposedly name. When philosophers argue about “fortune,” “motion,” or “element,” they are often fighting over words that have no clear referent. The Idols of the Theater (aphorisms 69-77) are the false systems of philosophy that have been constructed like stage plays — elaborate, internally consistent, and completely fictional. Bacon names three main kinds: the Sophistical (Aristotle’s logic-based system), the Empirical (the alchemists’ narrow experimentalism), and the Superstitious (philosophies that mix theology with natural philosophy, like Plato’s).
The remaining aphorisms of Book I (78-130) offer Bacon’s positive recommendations. He argues for a new kind of induction — one that proceeds by rejection and exclusion, not by simple enumeration. The true method begins with a Table of Discovery that organizes phenomena, then performs a Negative Instance analysis that eliminates false causes, and finally reaches a First Vintage — a provisional conclusion. This is the “ladder of the understanding” by which we ascend from particulars to axioms. Book I concludes with Bacon’s famous image of the ants, the spiders, and the bees: the empiricists are like ants, who merely collect and use what they find; the rationalists are like spiders, who spin webs from their own substance; but the true natural philosopher is like the bee, who gathers raw material from the flowers but then transforms it through its own power into something new — honey. The new method will combine empirical observation with intellectual processing, producing knowledge that is both grounded in nature and productive of works.
Book I (continued): The Idols of the Mind — The Four Classes
We are still within the first book of the *Novum Organum*, where Bacon is clearing the ground for his new method by diagnosing the sources of human error.
Having established the fallen state of human understanding in Aphorisms 1–37, Bacon now turns to the systematic identification of the four classes of Idols — the false notions that “beset men’s minds” and block access to truth. He introduces these in Aphorism 38 with a striking medical metaphor: just as physicians must first identify the diseases before prescribing remedies, so the interpreter of nature must first expose the “Idols and false notions which are now in possession of the human understanding, and have taken deep root therein.” The four classes are: Idols of the Tribe (*Idola Tribus*), Idols of the Cave (*Idola Specus*), Idols of the Marketplace (*Idola Fori*), and Idols of the Theatre (*Idola Theatri*).
The Idols of the Tribe arise from human nature itself — from the fact that “the human understanding is like a false mirror, which, receiving rays irregularly, distorts and discolors the nature of things by mingling its own nature with it.” These are errors common to all humanity, not merely to particular individuals or schools. Bacon identifies several specific manifestations: the tendency of the human intellect to “suppose a greater degree of order and equality in things than it really finds” — as when we imagine celestial bodies moving in perfect circles or posit correspondences and symmetries that nature does not actually exhibit. The understanding is also “moved by those things which strike the sense suddenly and are most vivid” rather than by things that are “fainter and less observed,” leading us to be swayed by what is immediate and striking rather than what is systematically true. Most importantly, “the human understanding is no dry light, but receives an infusion from the will and affections” — we believe what we prefer to be true, and “numberless are the ways, and sometimes imperceptible, in which the affections color and infect the understanding.”
The Idols of the Cave are the errors peculiar to each individual. Every person, Bacon explains, “has a cave or den of his own, which refracts and discolors the light of nature.” These arise from each person’s particular education, reading, the authorities they admire, the impressions that first struck them, and the temperament of their mind. Some become obsessed with the smallest differences between things, others with the broadest similarities; some are devotees of antiquity, others embrace novelty; some fixate on the study of particular bodies like the sun or the moon, unable to see things as part of a larger whole. “The human understanding,” Bacon warns, “is no dry light, but receives an infusion from the will and affections” — a line he repeats for emphasis across both tribe and cave idols, driving home the point that the passions are the most persistent corrupters of judgment.
“The Idols of the Tribe have their foundation in human nature itself, and in the tribe or race of men. For it is a false assertion that the sense of man is the measure of things. On the contrary, all perceptions as well of the sense as of the mind are according to the measure of the individual and not according to the measure of the universe.”
Book I (continued): The Idols of the Marketplace and Theatre
We now move to the remaining two classes of idols, which Bacon considers the most troublesome of all.
The Idols of the Marketplace are the most troublesome of all, because they “creep into the understanding through the alliance of words and names.” Men believe that their reason governs words, Bacon argues, but “it is also true that words, in their turn, react on the understanding.” Badly chosen words obstruct the understanding, leading to “innumerable controversies and idle fancies” through two specific mechanisms. The first is when names are given to things that do not exist at all — like “Fortune, the Prime Mover, the Orb of the Planets, [and] the Element of Fire” — fictions that people treat as real because they have names. The second, and more insidious, is when names exist for real things but are “confused and ill defined,” drawn from vulgar conceptions rather than from nature. Bacon points to the word “moist” as an example: it may signify water, or any fluid, or anything that flows easily, or anything that wets something else; such “ill-defined names” generate endless verbal disputes that are mistaken for substantive disagreements.
The Idols of the Theatre are those that “have migrated into men’s minds from the various dogmas of philosophies, and also from wrong laws of demonstration.” Bacon calls them idols of the theatre because “in my judgment all the received systems are but so many stage-plays, representing worlds of their own creation after an unreal and scenic fashion.” He does not mean merely that philosophers have been wrong — he means that they have constructed complete fictional universes, more elegant and coherent than the actual world, and their followers have taken these fictions for reality. Bacon classifies these false philosophies into three main species: the Sophistical, which “catch and carry away the understanding by matters of common occurrence” but fail to penetrate deeper; the Empirical, which “from a few and limited experiments” leap to vast generalizations and force everything to fit them; and the Superstitious, which “mingle philosophy with theology and traditions” and build systems on fanciful spiritual principles. These three species correspond roughly to the Aristotelian tradition, the alchemical tradition, and the Platonic or theological tradition.
What makes the Idols of the Theatre so dangerous, Bacon insists, is that they present themselves as complete and finished systems. Unlike the Idols of the Marketplace, which corrupt our everyday discourse, or the Idols of the Cave, which distort individual perception, these philosophical idols command entire schools and institutions. They have the weight of tradition, the authority of great names, and the appearance of systematic coherence. Yet they are no more real than the plays of the stage: “And it is not only the entire systems that are subject to this illusion, but also the principles and axioms derived from them, which by tradition and authority take hold of the mind.”
Book I (continued): Signs of False Systems
Bacon now turns from the diagnosis of the idols to a series of criteria by which existing philosophies can be recognized as inadequate.
In Aphorisms 67–77, Bacon presents what he calls “signs” or “proofs” that existing systems of philosophy are not merely incomplete but fundamentally corrupted. The first sign is the meagerness of their fruit: “The fruit and works of philosophy are the surest witnesses of its truth.” Greek philosophy, though “celebrated” and “elaborate,” has for two thousand years produced almost nothing “that tends to the relief or benefit of man.” It has produced no inventions, no practical arts, no increase in human power over nature. A true philosophy, Bacon insists, should be judged by its works, not by its elegance or its internal consistency. The second sign is that existing philosophies make no progress over time. In the mechanical arts — sailing, printing, artillery — each generation builds on the last, and knowledge accumulates. But in philosophy, the situation is reversed: “the earliest opinions are received and maintained, while those of later times are thrown aside.” The authority of Aristotle, Plato, or the early Church Fathers is taken as final, and any departure is treated as novelty or heresy. A field that does not advance with time is not a living science but a dead dogma.
The third sign is that controversies are endless and never resolved. When philosophers debate the same questions for centuries without any progress toward agreement — “when the same arguments are still in use, the same points are still urged pro and con” — this is a sure indication that their method is fundamentally flawed. True natural philosophy, properly conducted, “would put an end to disputes” by producing demonstrable results that no one could deny. The fourth sign is the internal weakness of the existing systems themselves: they are “full of gaps and empty spaces,” they rely on “abstract and general terms” that have no clear reference to actual things, and they contain “many things which are mere words and nothing more.”
“Philosophy, when it is cultivated by men of sound understanding and steady application, leads to rich and fruitful works; but when it falls into the hands of men of quick wit and ingenious discourse, it degenerates into empty and subtle disputations.”
Bacon adds a further sign drawn from the history of philosophy itself: the despair of success that has overtaken many thinkers. Because the existing systems have failed so thoroughly, many of the best minds have abandoned the project of interpreting nature altogether and retreated into skepticism. This despair, Bacon argues, is “one of the greatest causes of the perversion and weakness of the sciences.” It is a rational response to the failures of current methods — but it is also unnecessary, because a new method will succeed where the old ones have failed. The fault lies not with human capability but with human procedure.
Book I (continued): Causes of Error and Grounds of Hope
Bacon now provides a deeper analysis of why human knowledge has been so slow to advance, and why there is nevertheless reason for hope.
In Aphorisms 78–92, Bacon addresses the causes of error that have kept natural philosophy in its infant state for so many centuries. He identifies several: the narrowness of human life and experience (the fact that each person lives too short a time, travels too little, and encounters too few phenomena); the lack of systematic experimentation; the contempt for practical arts and mechanical matters among learned men; the authority of ancient philosophers, which “has held men back from advancing beyond what was discovered by the ancients”; the fear of innovation, which “is the chief obstacle to the success of any new system”; and — perhaps most importantly — the absence of any true method for interrogating nature. The sciences have not advanced because men have been “carried along by the stream of custom, by the wind of doctrine, and by the eddies of controversy.”
But then Bacon pivots dramatically, turning from these causes of despair to the grounds of hope. If the existing systems were based on reason and evidence, their long failure would be discouraging; but since they are based on “vain and idle” methods, their failure tells us nothing about the prospects of a true method. Bacon offers eight specific grounds for hope. First, “the discoveries of the ancients” were not really discoveries at all but “the offspring of their own genius” — they found nothing because they looked for nothing in the right way. Second, “the very nature of things” favors a method that proceeds gradually and patiently, rather than leaping to generalities. Third, the mechanical arts have shown steady progress precisely because they are “practiced by men who are not carried away by the subtleties of speculation.” Fourth, the invention of printing, gunpowder, and the compass in comparatively recent times proves that the human race is not in decline but is capable of great discoveries when the conditions are right.
“It would be disgraceful if, while the regions of the material globe — that is, of the earth, of the sea, and of the stars — have been in our age laid open and disclosed, the limits of the intellectual globe should be restricted to the narrow discoveries of the ancients.”
The remaining grounds of hope include the fact that the true path to knowledge has never been tried; that the human intellect, though weak, is capable of being “aided and fortified” by proper instruments; that the sea of particulars is not infinite but navigable with careful method; and finally that “the fates of the human race” seem to be calling for a renewal of natural philosophy — the time is ripe, and the conditions are favorable in a way they have not been since the age of the Greeks. Bacon is not merely describing a method; he is issuing a summons to an entire civilization to abandon its intellectual errors and embark on a new enterprise.
Aphorisms Concerning the Interpretation of Nature and the Kingdom of Man — Book II: The Investigation of Forms (Aphorisms I–X)
We now enter the second book of the *Novum Organum*, where Bacon shifts from the destructive critique of false methods to the constructive presentation of his own system. This section lays the foundation for his new logic — the Interpretation of Nature — which stands in direct opposition to the syllogistic logic of the schools.
Bacon opens Book II by declaring that the work of the human mind in natural philosophy has two principal parts: “the first, to educe or extract axioms from experience; the second, to deduce or derive new experiments from axioms.” The former is the more difficult and the more neglected, and it is to this that Bacon devotes his attention. He insists that the true method proceeds by a “gradual and continuous ascent” from particulars to lower axioms, then to middle axioms, and finally to the most general axioms — but never by leaping at once to the highest generalizations. The middle axioms, he says, are “the true and solid and living axioms, on which the affairs and fortunes of men depend.”
The central concept of Book II is the investigation of Forms. Bacon defines a Form as “the true difference, or natura naturans (nature-making nature), or source from which the given nature flows.” To know the Form of a nature — such as heat, whiteness, or weight — is to know the cause that is “always present when the given nature is present, always absent when it is absent, and always varies as it varies.” The Form is not an abstract Platonic idea but the law of the nature itself, the underlying structure from which the phenomenon necessarily follows.
Bacon then presents his method for discovering Forms through three tables of presentation. The first is the Table of Essence and Presence, which collects instances in which the given nature appears in diverse and unrelated subjects. For heat, these include the rays of the sun, flame, boiling liquids, friction, animal bodies, and many more. The second is the Table of Deviation, or of Absence in Proximity, which lists instances where the nature is absent but closely related to cases where it is present. For heat, this includes moonlight (which gives light but not heat), the air between the sun and the earth, and living creatures at the moment of death. The third is the Table of Degrees, or of Comparison, which records instances where the nature appears in greater or lesser degree, showing how it increases or decreases with other conditions.
“The investigation of Forms proceeds thus: a nature being given, we must first present to the understanding all the known instances which agree in that nature, though in subjects the most dissimilar. And this collection must be made in the manner of a history, without premature speculation or any great subtlety.”
Bacon insists that these tables are not the end of the inquiry but only the beginning — they are the raw material from which the understanding must work. The next step is the Exclusion or rejection of those natures that are not the Form. This is the process of eliminating all candidates that fail to satisfy the conditions of presence, absence, and variation. Bacon calls this the First Vintage or first harvest of the inquiry, and he warns that it is a difficult and laborious task.
The significance of this procedure is profound: Bacon is attempting to replace the haphazard, intuition-driven guesswork of traditional natural philosophy with a systematic, public, and repeatable method. The investigator does not simply think about the nature in question; he compiles a natural history of its appearances, eliminates impossible causes, and then, through a process of induction that is far more rigorous than simple enumeration, arrives at the true Form. This is not deduction from first principles, nor is it the accumulation of anecdotes; it is a method for extracting laws from the data of experience itself.
Aphorisms XI–XX: The Prerogative Instances
Having laid out the general method of tables and exclusion, Bacon now introduces a set of special tools for accelerating and refining the investigation. These are the Prerogative Instances — particular types of cases that have exceptional power to reveal the structure of nature. He presents twenty-seven kinds in total, of which the first several are covered in these aphorisms.
The first and most important are Solitary Instances (or Instances of the Fingerpost), which exhibit the given nature in subjects that share nothing else in common, and conversely exhibit its absence in subjects that share everything else. These instances “point out and indicate the Form at once,” like a fingerpost at a crossroads, because they eliminate so many alternative explanations. Bacon gives the example of heat: the sun’s rays and the heat of a living animal share heat but differ in almost every other respect, so the Form of heat must be something that can exist in both.
Next come Migratory Instances, which show the nature coming into being or passing away before the investigator’s eyes. These are valuable because they reveal the conditions under which the nature appears and disappears, allowing the exclusion of causes that are not present at the moment of change. For heat, the sudden generation of heat by friction or the extinction of a flame by smothering are migratory instances.
The third kind are Ostensive Instances (or Glaring Instances), which show the nature in its most intense, pure, and unadulterated form. These instances “strike the sense immediately and manifestly.” For heat, the sun’s rays concentrated by a burning glass are more ostensive than the diffuse warmth of a fire. Such instances are valuable because they make the nature’s behavior easier to observe and measure.
“Among the prerogative instances I will first mention the Solitary Instances, or those which exhibit the nature in question in subjects that have nothing in common with other subjects except that nature; and also those which exhibit it in subjects that have everything in common with others except that nature. For these instances plainly cut off all superfluous circumstances, and bring the inquiry to a point.”
Bacon then continues with Clan Instances (or Parallel Instances), which show how different natures vary together — for example, where heat increases, expansion also increases; where heat decreases, contraction follows. These suggest a relationship between natures that may reveal the Form indirectly. He also introduces Limit Instances (or Boundary Instances), in which the nature approaches its extreme or its point of transformation. The boiling point of water, the melting point of metal, or the threshold of audibility are limit instances that often reveal the underlying structure of the phenomenon.
The purpose of these categories is not to multiply distinctions for their own sake, but to provide the investigator with a repertoire of strategic questions. When confronted with a new nature to investigate, the natural philosopher should actively search for solitary instances, migratory instances, ostensive instances, and the rest, rather than passively collecting whatever experience happens to present. The prerogative instances are, in effect, a checklist for systematic inquiry — a way of ensuring that the data gathered are as revealing and as decisive as possible.
Aphorisms XXI–XXXVII: Further Prerogative Instances and the First Vintage
Bacon continues his enumeration of prerogative instances, moving through Instances of the Cross (or Decisive Instances), Instances of the Road, Instances of the Course, and others, each with its own special function in the investigation. The Instances of the Cross are particularly important: they are cases where two competing explanations make contrary predictions, and the outcome of the experiment “decides the question” between them. Bacon compares them to the cross at a crossroads, where the traveler must choose one path or the other.
He then turns to the crucial concept of the First Vintage — the initial hypothesis or “first harvest” that emerges from the tables and exclusion. Using heat as his extended example, Bacon performs the actual work of the method. After compiling the tables of presence, absence, and degrees, and after excluding obvious non-causes (such as light, rarity, and fluidity), he arrives at a preliminary definition: “Heat is a species of motion — a motion that is expansive, restrained, and acting in a certain way upon the smaller particles of bodies.”
This is a remarkable moment in the text: Bacon is not merely describing a method in the abstract, but actually demonstrating it on a concrete problem. He specifies that the motion of heat is not the gross motion of the whole body (as in a rotating wheel) but an internal motion of the minute particles, and that this motion is characteristically upward and vibratory rather than circular or linear. He compares it to the motion of a bird in a cage, struggling to escape but held back — a restless, striving motion that is both expansive and constrained.
“From these instances, therefore, the nature of which heat is a particular case seems to be motion. This is the first vintage, but it is still a preliminary and tentative result, to be confirmed or corrected by further investigation.”
Bacon then adds several constraints on this definition. The motion of heat is not merely expansive (for air expands when heated but also when rarefied without heat), but expansive with a certain character: it is “a motion of expansion, checked and repelled, and striving to burst forth.” Moreover, it is not uniform throughout the body but acts most intensely on the smaller particles — the corpuscles of the substance — causing them to vibrate and struggle against one another. This is why friction generates heat: the rubbing of surfaces excites this internal motion in the particles.
The aphorisms conclude with a series of Cautions and Precepts for the application of the method. Bacon warns against premature generalization, against the seduction of elegant hypotheses, and against the tendency to rest content with the first vintage. The true interpretation of nature requires repeated testing, variation of conditions, and the gradual accumulation of middle axioms before any universal law can be safely asserted. He also emphasizes that the Forms discovered by this method are not metaphysical entities but operative principles — knowledge that enables the production of effects.
Aphorisms XXXVIII–LII: The Doctrine of the Instruments of the Mind
Bacon now steps back from the detailed procedure to reflect on the instruments that the mind requires for the work of interpretation. He distinguishes between two kinds of instruments: those that aid the senses and those that aid the understanding. The senses, he argues, are naturally weak and easily deceived; they must be supplemented by experiments that bring hidden phenomena into clear view. But even more important are the instruments that aid the understanding — the true rules of interpretation that prevent the mind from leaping to false conclusions.
He introduces the distinction between the Anticipation of Nature and the Interpretation of Nature. The Anticipation is the mind’s natural tendency to guess at causes from superficial experience — this is what all previous philosophy has done. The Interpretation, by contrast, proceeds methodically from particulars to axioms through the tables and exclusion. Bacon insists that these two approaches are incommensurable: “the one is like the *Anticipation of Nature*, the other the *Interpretation of Nature*.” They cannot be combined or reconciled; the philosopher must choose one path or the other.
The key to successful interpretation, Bacon argues, lies in the rejection of the syllogism as the primary instrument of natural philosophy. The syllogism consists of propositions, propositions consist of words, and words are the symbols of notions — but if the notions themselves (such as substance, quality, act, passion, and matter) are confused and ill-defined, then the entire structure built upon them is unsound. Bacon calls for a purification of the notions of natural philosophy, beginning with the simplest and most fundamental concepts.
“The syllogism is not applied to the first principles of sciences, and is applied in vain to middle axioms, since it is far too subtle for the mass of nature. It commands assent, therefore, but does not take hold of the thing.”
Bacon then categorizes the degrees of certainty that the new method can achieve. He distinguishes between three levels: experiments of light (which reveal the causes of phenomena), experiments of fruit (which produce useful results), and the axioms themselves (which are the permanent laws of nature). The goal of the Instauration is not merely to produce useful inventions — though these will follow — but to establish true and certain axioms from which any number of inventions can be derived.
The aphorisms conclude with a reflection on the relation between the old and the new philosophy. Bacon acknowledges that many will reject his method because it is unfamiliar and difficult, but he insists that the difficulty is in the nature of the task, not in any flaw of the method itself. He compares the Interpretation of Nature to the work of a sculptor who must first remove the excess marble before the statue can emerge — the tables, the exclusion, the first vintage, and the prerogative instances are all tools for removing the obstacles that prevent the truth from appearing.
Aphorisms LIII–LXV: The Scales of Interpretation and the New Induction
The final section of Book II’s extant aphorisms (for the work was left incomplete) introduces the Scales of Interpretation — a series of graduated steps by which the understanding ascends from particular instances to the most general axioms. Bacon lists nine particular instances that serve as the supports or helps for the understanding, each corresponding to a stage in the interpretive process.
The first scale is the Table of Discovery (the three tables already described). The second is the Process of Exclusion — the rejection of impossible causes. The third is the Negative Instance — the consideration of cases that contradict the tentative hypothesis. The fourth is the Cross Instance — the decisive experiment that chooses between alternatives. The fifth is the Migration of Nature — the observation of the nature as it comes into being. The sixth is the Limit Instance — the extreme case. The seventh is the Transformation of Nature — the artificial production of the nature through controlled conditions. The eighth is the Comparison of Natures — the analogy between different phenomena. The ninth is the Dividing of Nature — the analysis of compound natures into their simple components.
Bacon then introduces the crucial concept of the Induction by Rejection — the method by which the understanding eliminates false causes and converges on the true Form. This is not the “induction by simple enumeration” that children and common sense use (e.g., “all swans I have seen are white, therefore all swans are white”), but a logically rigorous process of exclusion that considers the full range of possible causes and eliminates those that do not satisfy the required conditions.
“The induction which is to be available for the discovery and demonstration of sciences must analyze nature by proper rejections and exclusions, and then, after a sufficient number of negatives, conclude on the affirmative.”
The final aphorisms turn to the practical application of the method. Bacon insists that the Interpretation of Nature is not a speculative exercise but a tool for the relief of the human condition. The knowledge of Forms enables the production of effects: if we know the Form of heat, we can generate heat at will; if we know the Form of life, we can prolong or restore it; if we know the Form of gold, we can transmute base metals. This is the Kingdom of Man — the dominion over nature that comes only through obedience to nature’s laws.
The work ends abruptly, with Bacon promising to continue with further examples and applications but never completing the task. The extant *Novum Organum* contains only 82 aphorisms in Book I and 52 in Book II — a fragment of the grand design Bacon had envisioned. Yet even in this incomplete form, the work establishes the foundations of modern scientific method: the primacy of observation, the systematic collection of data, the rigorous exclusion of false causes, the gradual ascent to general laws, and the ultimate goal of human power over nature.
The Preparatory History of Natural and Experimental History
Bacon now turns to the actual content of the Natural and Experimental History that must form the foundation of all legitimate natural philosophy. This section is drawn from Bacon’s plan for the sixth part of the Great Instauration, which he calls the “preparatory history” — the raw material upon which the new method is to operate. The work opens with a declaration of the absolute necessity of this historical foundation: without a comprehensive collection of natural facts, the Interpretation of Nature can never proceed.
The key passage reads:
“The whole of the work which I have proposed to myself must be preceded by a Natural and Experimental History, which may serve as a foundation for philosophy. For my method of discovering sciences is such as leaves but little to the acuteness and strength of men’s wits, but places all wits and understandings nearly on a level.”
Bacon then lays out the three kinds of natural history that must be compiled. The first is History of Generations — the record of nature in her ordinary course, including the phenomena of the heavens, the earth, the sea, the air, and all living creatures. The second is History of Pretergenerations — the record of nature in her aberrations or deviations, including monsters, prodigies, and all that is unusual or rare in nature. The third is History of Arts — the record of nature under constraint, as she appears in the mechanical arts, in experiments, and in all human interventions that force nature to reveal her secrets.
Bacon insists that this history must be “copious and various” — it must collect facts from every region of the world, from every period of time, and from every art and craft. The history must be drawn not only from books and learned men but from the practical experience of artisans, farmers, sailors, and all who work with nature directly. Bacon particularly emphasizes the importance of studying the mechanical arts, for in these arts nature is put to the question and compelled to yield answers she would not freely give.
The collection of this history must follow strict methodological principles. All facts must be recorded with their precise circumstances — the time, place, and conditions under which they occurred. Unreliable witnesses must be noted as such, and doubtful facts must be marked with a sign of uncertainty. The history must distinguish between facts that are certain, facts that are probable, and facts that are merely reported. Above all, the history must avoid the corruption of anticipations — the facts must be recorded as they are, not as the recorder wishes them to be.
Bacon adds that this history must include experiments as well as observations — not only what nature does of herself, but what nature does when we put her to the test. These experiments must be systematically varied and repeated, and their results must be recorded with the same precision as natural observations. The purpose is not merely to accumulate facts but to create a body of evidence that will serve as the basis for true induction.
The meaning of this preparatory history is fundamental to the entire Baconian project. Bacon is arguing that the first step in the renewal of science is not the development of theories or the application of logic, but the systematic collection of facts. The human mind must humble itself before nature and receive her testimony before it presumes to interpret her. This history is the foundation upon which the entire edifice of natural philosophy is to be built — and without this foundation, the superstructure will inevitably fall.
The Catalogue of Particular Histories
Bacon provides a detailed catalogue of the particular histories that must be compiled for the Great Instauration. This catalogue covers one hundred and thirty specific topics, organized under the three classes of natural history: generations, pretergenerations, and arts. The list is remarkable both for its comprehensiveness and for its specificity — Bacon leaves no area of nature unexplored.
The first division, the History of Generations, includes: the history of the heavens and the stars; the history of the celestial regions and their motions; the history of the planets and their aspects; the history of the fixed stars and their magnitudes; the history of comets and meteors; the history of the sun and its light; the history of the moon and its phases; the history of the eclipses and their periods; the history of the air and its winds; the history of the ether and its nature; the history of the seasons and their variations; the history of the earth and its parts; the history of the seas and their tides; the history of rivers and lakes; the history of mountains and valleys; the history of minerals and their properties; the history of plants and their growth; the history of animals and their generations; the history of man and his body — including the history of sleep, of dreams, of digestion, of respiration, of the senses, of the passions, and of all the operations of the human frame.
The second division, the History of Pretergenerations, includes: the history of monsters and prodigies; the history of all unusual births and deformities; the history of all strange and wonderful phenomena in nature; the history of all extraordinary powers and properties; the history of all novelties and rarities in every natural kind; the history of all diseases and their cures; the history of all deaths and their causes; the history of all natural miracles and their circumstances.
The third division, the History of Arts, includes: the history of agriculture and its practices; the history of gardening and horticulture; the history of cooking and the preparation of food; the history of brewing and fermentation; the history of baking and the making of bread; the history of the making of wine and other drinks; the history of metallurgy and the working of metals; the history of mining and the extraction of minerals; the history of glass-making and the working of glass; the history of ceramics and the making of pottery; the history of weaving and the making of cloth; the history of dyeing and the coloring of materials; the history of building and architecture; the history of shipbuilding and navigation; the history of printing and the book arts; the history of the making of instruments, both mathematical and musical; the history of the mechanical arts — including the making of clocks, of mills, of pumps, of engines of all kinds; the history of the chemical arts — including distillation, sublimation, calcination, and all other operations of the laboratory; the history of medicine and surgery; the history of alchemy and its transmutations; the history of magic and its pretended operations.
Bacon concludes the catalogue with the instruction that these histories must be compiled by the collaborative effort of many workers. No single man can accomplish so vast a task. Therefore, Bacon calls for the establishment of a college or society of natural historians, each assigned to a particular department of nature, all working according to the same methodological principles, and all communicating their results to a central repository.
The importance of this catalogue lies in its demonstration of the scope of the Baconian project. Bacon is not proposing a modest reform of natural philosophy — he is proposing a complete reconstitution of human knowledge, covering every aspect of nature and every human art. The catalogue makes clear that the Great Instauration is not merely a philosophical program but a practical enterprise of immense proportions, requiring the organized labor of many minds over many generations.
The Distribution of the Work
Bacon provides a brief outline of how the collected materials of the Natural and Experimental History are to be organized and presented. The work is to be divided into centuries — collections of one hundred experiments or observations each — with each century forming a coherent unit. This organization is not merely mechanical but reflects Bacon’s conviction that natural history must be arranged in a way that facilitates comparison and induction.
The first century is to contain experiments and observations that are simple and fundamental — those that reveal the most basic properties of bodies and the most elementary operations of nature. These include experiments on the nature of heat, of light, of sound, of motion, of density, of rarity, of the hot and the cold, of the moist and the dry. Bacon calls these “the alphabet of nature” — the simple elements out of which all more complex phenomena are composed.
The subsequent centuries are to contain experiments of increasing complexity, arranged so that each century builds upon the knowledge gained in the preceding ones. The ordering follows the method of induction itself — from the simplest observations to the most general laws, from the most elementary properties to the most complex compositions.
Each century is to be preceded by a brief preface explaining the purpose and arrangement of the experiments it contains. Each experiment is to be described with its exact circumstances, its results, and any observations that arose during its performance. Doubtful experiments are to be marked as such, and failed experiments are to be recorded alongside successful ones — for the knowledge of what does not work is as important as the knowledge of what does.
Bacon further specifies that the experiments are to be drawn from three sources: from the records of previous naturalists and experimenters, from the practical arts and crafts, and from new experiments performed at Bacon’s direction by his assistants. The first two sources are to be treated critically, with all doubtful reports examined and, where possible, tested by experiment. The third source — new experiments — is to be the most valuable, for these are performed with the specific purpose of illuminating the Forms of nature.
The distribution concludes with Bacon’s instruction that the work is to be published piecemeal, as each century is completed. The reason is practical: the work is too vast to be delayed until its completion, and the immediate publication of partial results will allow other naturalists to test and extend them. Bacon compares this method to the building of a house — the foundations must be laid first, but the walls and roof can be added as materials become available.
This distribution reveals Bacon’s practical genius. He is not merely a philosopher speculating about method — he is an organizer of knowledge, designing a system that can be executed by ordinary human beings working over many years. The arrangement of experiments in centuries, the careful documentation of results, the progressive building of knowledge — all these reflect Bacon’s understanding that the renewal of science requires not only new ideas but new institutions and new ways of organizing intellectual labor.
The Beginning of the Natural History: Experiments on the Nature of Heat
Bacon begins the actual work of natural history with a series of experiments on the nature of heat. These experiments are the first fruits of the method outlined in the *Novum Organum*, and they demonstrate in practice how the interpretation of nature is to proceed. The experiments are presented in the form of a Table of Presence — a systematic collection of instances in which heat appears, arranged for the purpose of discovering the Form of heat.
The first experiment concerns the rays of the sun. Bacon reports that the sun’s rays, when concentrated by a burning glass, produce intense heat. This heat is greater when the glass is larger and when the sun is higher in the sky. The heat of the sun’s rays is different from other heats in that it is penetrating — it passes through transparent bodies without heating them, but produces heat when it falls on opaque bodies.
The second experiment concerns the heat of fire. Bacon describes the properties of flame, of red-hot iron, of boiling water, of steam, and of the heat produced by chemical reactions. He notes that fire consumes bodies, turning them into ash or smoke, while other forms of heat may warm bodies without consuming them. Fire requires fuel and air — without these, it cannot continue.
The third experiment concerns the heat produced by motion. Bacon reports that the rubbing of two bodies together produces heat — as when a man rubs his hands together, or when the axles of wheels are heated by friction. A nail driven rapidly into a board becomes hot. A metal bar bent repeatedly back and forth becomes hot at the point of bending.
The fourth experiment concerns the heat produced by living bodies. Animal bodies are warm, and the heat is greatest in the heart and the vital organs. The heat of living bodies is different from other heats in that it is vital — it is accompanied by life, and it ceases when life ceases.
The fifth experiment concerns the heat of fermentation. New wine ferments and becomes warm. Dung heaps heat up as they decompose. Moist hay stacked together becomes so hot that it can burst into flame.
The sixth experiment concerns the degrees of heat — the measurement and comparison of different heats. Bacon reports that the heat of boiling water is less than that of flame, and that the heat of flame is less than that of red-hot iron. Some heats are so intense that they destroy all bodies — as in the heat of a furnace, or the heat of lightning.
The seventh experiment concerns the direction of heat — the way heat moves through bodies. Heat moves from hotter bodies to colder ones. Heat moves more quickly through some bodies (metals) than through others (wood, stone). Heat tends to rise upward — the air above a fire is hotter than the air at the sides.
The eighth experiment concerns the effects of heat — what heat does to bodies. Heat expands bodies — both solids and liquids expand when heated. Heat rarefies bodies — turns solids into liquids and liquids into vapor. Heat alters the colors of bodies — black becomes red, red becomes white. Heat alters the powers and properties of bodies — food is cooked, metals are softened, medicines are changed.
Bacon concludes this first installment of the natural history with the observation that all these experiments and observations are merely the beginning. Many more experiments are needed — experiments on the cold, on the properties of bodies, on the operations of nature — before the Form of heat can be established with certainty. But the collection of data has begun, and the method is now clear: nature must be interrogated by experiment, and her answers must be recorded faithfully.
This natural history of heat is crucial for understanding Bacon’s method in practice. The experiments are not chosen at random — they are designed to reveal the universal conditions under which heat appears. By collecting instances of heat from the sun, from fire, from motion, from life, and from fermentation, Bacon is creating the Table of Presence that, together with the Table of Absence and the Table of Degrees, will allow the induction that discovers the Form of heat. The work demonstrates that the new method is not merely a theoretical program but a practical procedure that can be applied to any natural phenomenon.
Experiments on the Nature of Cold
Bacon continues the natural history with a parallel investigation of cold. This section mirrors the investigation of heat, collecting instances of cold from all the sources where cold appears. The purpose is the same — to create a comprehensive Table of Presence for cold, which will serve as the foundation for discovering the Form of cold.
The first experiments concern the cold of the atmosphere. In winter, the air becomes cold, and this cold increases as one moves toward the poles. The cold is greater at night than during the day, and greater at high altitudes than at low ones. The wind increases cold, and damp air feels colder than dry air at the same temperature.
The second experiments concern the cold produced by evaporation. When water evaporates, it produces cold — as when a wet cloth is hung in the wind, or when alcohol is rubbed on the skin. The more rapid the evaporation, the greater the cold. Some liquids — like ether and spirit of wine — produce intense cold when they evaporate.
The third experiments concern the cold of the earth. Deep caves and mines are cold, and this cold is constant throughout the year. Ground that has been shaded from the sun remains cold longer than ground that has been exposed. The earth’s cold penetrates upward and can cool the air above it.
The fourth experiments concern the cold produced by chemical reactions. When salt is mixed with snow or ice, the mixture becomes colder than either alone — so cold that it can freeze water. The dissolution of some salts in water produces cold, while the dissolution of others produces heat.
The fifth experiments concern the cold of living bodies. Some animals — like fish and frogs — are cold-blooded. Plants are cold compared to animals. The bodies of dead men are cold, and this cold increases as decay proceeds.
The sixth experiments concern the degrees of cold — the measurement and comparison of different colds. Bacon reports that the cold of winter in northern regions is more intense than the cold of a cellar or a cave. Some colds are so intense that they kill plants and animals, freeze rivers solid, and split rocks.
The seventh experiments concern the effects of cold — what cold does to bodies. Cold contracts bodies — solids and liquids shrink when cooled. Cold consolidates bodies — turns liquids into solids and vapors into liquids. Cold alters the properties of bodies — makes them brittle, changes their color, affects their taste and smell.
Bacon notes that the investigation of cold is more difficult than the investigation of heat, because we cannot produce cold as easily as we can produce heat. We have furnaces and fires, but we have no equivalent machines for producing intense cold. Nevertheless, the same method must be applied — the systematic collection of instances, the careful observation of circumstances, the comparison of degrees.
The investigation of cold demonstrates the symmetry of Bacon’s method. Heat and cold are opposites, and the same method that reveals the Form of heat will reveal the Form of cold. By investigating nature through pairs of opposites, we can discover the underlying principles that govern both. This approach anticipates Bacon’s doctrine of the scales of nature — the continuous gradation from one extreme to another that reveals the true structure of natural phenomena.
Experiments on the Nature of Light
Bacon proceeds to the investigation of light, applying the same method of systematic collection and comparison. The natural history of light is particularly important because light is one of the most subtle and difficult of natural phenomena — it seems almost immaterial, yet it has real effects on bodies.
The first experiments concern the sources of light. The sun is the greatest source of light, followed by the stars, by fire, by lightning, by decaying wood, by certain animals (like fireflies and glowworms), and by the eyes of some animals (like cats). Light can also be produced by friction — as when a flint is struck against steel, or when a diamond is rubbed.
The second experiments concern the propagation of light. Light travels in straight lines — it cannot turn corners. Light travels through transparent bodies — air, water, glass — but is stopped by opaque bodies. Light travels with incredible speed — the light of the sun reaches the earth in a few minutes, though the distance is immense.
The third experiments concern the reflection of light. Light is reflected from the surfaces of bodies, and the angle of reflection equals the angle of incidence. Smooth surfaces reflect more light than rough ones. The reflection of light from a mirror produces an image that appears behind the mirror.
The fourth experiments concern the refraction of light. When light passes from one transparent medium into another, it is bent — as when a stick is placed in water and appears broken. The degree of bending depends on the nature of the media and the angle at which the light strikes the surface.
The fifth experiments concern the colors of light. When light passes through a prism, it is separated into different colors — red, orange, yellow, green, blue, indigo, violet. These colors can be recombined to form white light. Different bodies appear in different colors because they absorb some colors and reflect others.
The sixth experiments concern the effects of light. Light illuminates objects and makes them visible. Light produces heat when it is concentrated or absorbed. Light affects plants — they grow toward light and become pale without it. Light affects animals — many animals sleep in darkness and are active in light. Light even affects the human spirit — darkness brings melancholy, while light brings cheerfulness.
Bacon observes that the nature of light is extremely difficult to understand because we cannot capture or hold it. Light seems to be a kind of motion — a rapid vibration or wave that passes through transparent media. But what this motion is, and how it produces the effects we observe, remains obscure.
The investigation of light reveals the limits of the method as well as its power. Some phenomena are so subtle and complex that many experiments are needed before the Form can be discovered. Bacon is not discouraged by this difficulty — he insists that with sufficient experiments, even the nature of light can be understood. The method is the same, whether we are investigating heat, cold, or light: collect instances, compare them, exclude what is not essential, and ascend gradually to the Form.
Experiments on the Nature of Sound
Bacon turns to sound, applying the same method of systematic investigation. Sound is a phenomenon of the air, produced by the vibration of bodies and transmitted through the air to the ear. The natural history of sound includes experiments on the production, propagation, reflection, and reception of sound.
The first experiments concern the production of sound. Sound is produced when bodies are struck, when they rub against each other, when they break, when they explode, when wind passes through narrow passages, when vocal cords vibrate, when strings are plucked, when bells are struck, when drums are beaten. Every sound requires a vibrating body — without vibration, there is no sound.
The second experiments concern the propagation of sound. Sound travels through the air, but it also travels through water and through solid bodies (as when one puts an ear to the ground to hear approaching horses). Sound travels more quickly through some media than through others — through air more quickly than through water, through solids more quickly than through air. The speed of sound is much less than the speed of light — we see lightning before we hear thunder.
The third experiments concern the reflection of sound. Sound is reflected from hard surfaces, producing echoes. The distance of the reflecting surface determines the time of the echo. Curved surfaces focus sound — as in the whispering galleries of some buildings. Multiple reflections produce multiple echoes.
The fourth experiments concern the pitch of sound — the difference between high and low sounds. Pitch depends on the frequency of vibration — rapid vibrations produce high sounds, slow vibrations produce low sounds. Short strings produce higher pitches than long ones, thin strings higher than thick ones, stretched strings higher than slack ones.
The fifth experiments concern the loudness of sound. Loudness depends on the amplitude of vibration — the greater the vibration, the louder the sound. The distance from the source also affects loudness — sound becomes fainter as it travels farther. The ear is more sensitive to some sounds than to others.
The sixth experiments concern the quality of sound — the difference between sounds of the same pitch and loudness from different sources. A flute sounds different from a violin playing the same note. The human voice is different from any musical instrument. Quality depends on the presence of overtones — additional frequencies that accompany the fundamental frequency.
Bacon notes that sound, like light, seems to be a kind of motion — a wave or vibration that passes through the air. But the motion of sound is different from the motion of light — sound requires a medium and cannot travel through a vacuum, while light can travel through empty space. This difference suggests that sound and light have different Forms — though both are propagated through media, the nature of the propagation is fundamentally different.
The investigation of sound demonstrates the importance of analogy in the interpretation of nature. By comparing sound with light, and both with heat, we can begin to understand the general principles that govern the propagation of motion through media. But analogy must be used with caution — it suggests possibilities, but only experiment can confirm them.
Experiments on the Nature of Air
Bacon now investigates the nature of air, which he considers one of the most fundamental of natural substances. Air is everywhere around us, yet its nature is difficult to grasp because it is invisible and intangible. The natural history of air includes experiments on its properties, its transformations, and its powers.
The first experiments concern the materiality of air. Air is a real substance, not a mere emptiness. It occupies space, it has weight, it resists motion. When a vessel is sealed and the air is pumped out, the vessel becomes lighter. When air is compressed, it resists — as when a bellows is squeezed with the opening closed.
The second experiments concern the weight of air. The atmosphere presses down on everything with a measurable weight. This pressure is what makes water rise in a pump — the air presses on the surface of the water and pushes it up the tube. The pressure decreases with altitude — on a mountaintop, the air is thinner and the pressure is less.
The third experiments concern the elasticity of air. Air can be compressed into a smaller space, and when released, it expands again. Compressed air is stronger than uncompressed air — it can drive machines, lift weights, project missiles. The elasticity of air is what makes the atmosphere a spring — pressing on everything, ready to expand when pressure is removed.
The fourth experiments concern the moisture of air. Air contains water vapor, which can be seen as mist or cloud, felt as humidity, collected as dew. The amount of moisture in the air varies with temperature and weather. Warm air holds more moisture than cold air — this is why dew forms on cold surfaces at night.
The fifth experiments concern the temperature of air. Air can be hot or cold, and its temperature changes with the seasons, the time of day, the altitude, and the presence of heat sources. Air transmits heat — it carries warmth from fires and cold from ice. Air can be heated by compression and cooled by expansion.
The sixth experiments concern the purity of air. Air is not a single substance but a mixture of different vapors and effluvia. The air near the earth is contaminated with exhalations from the ground, from plants, from animals, from decaying matter. The air at high altitudes is purer — it is more healthful, more transparent, more suitable for respiration.
Bacon observes that air is the medium through which many natural operations are performed. The air carries light, sound, heat, cold, odors, and the vapors that cause diseases. The air is the breath of life — animals and men cannot live without it. The air is the sphere of the winds — those great motions of the atmosphere that bring rain and drought, storm and calm.
The investigation of air reveals the importance of studying the media in which natural phenomena occur. Air is not merely empty space but a real substance with definite properties — elasticity, compressibility, moisture-carrying capacity. These properties affect all the phenomena that occur in the air — the propagation of light and sound, the production of heat and cold, the growth of plants and animals. By understanding the nature of air, we can understand the conditions under which all other natural phenomena take place.
Experiments on the Nature of Water
Bacon investigates the nature of water, that other great element that covers most of the earth’s surface and permeates all living things. The natural history of water includes experiments on its properties, its transformations, and its powers — parallel to the investigation of air, but with attention to the differences between these two great fluids.
The first experiments concern the fluidity of water. Water flows easily — it takes the shape of any container, it seeks its own level, it runs downhill. Water is much denser than air — a given volume of water weighs about 800 times more than the same volume of air. Water resists motion less than solids but more than air — a body moving through water experiences friction and drag.
The second experiments concern the compressibility of water. Unlike air, water is almost incompressible — it cannot be squeezed into a significantly smaller space. This property makes water useful for transmitting force — pressure applied to water in one part of a container is transmitted equally to all parts.
The third experiments concern the transparency of water. Pure water is transparent — light passes through it, though with some absorption and refraction. The transparency of water decreases as the water becomes more turbid or colored. Water absorbs light more strongly than air — in deep water, it becomes dark.
The fourth experiments concern the solution of substances in water. Water dissolves many substances — salt, sugar, minerals, gases. The ability to dissolve makes water the great agent of chemical change — it carries dissolved substances from place to place, deposits them in crystals, combines them with other substances.
The fifth experiments concern the evaporation of water. When heated, water turns into vapor — an invisible gas that rises into the air. This vapor can be condensed back into water by cooling. The evaporation of water is the engine of the hydrological cycle — water rises from the sea, forms clouds, falls as rain, and returns to the sea.
The sixth experiments concern the freezing of water. When cooled sufficiently, water turns into ice — a solid that is less dense than liquid water. This expansion upon freezing is remarkable — most substances contract when they solidify, but water expands. This property is why ice floats and why water pipes burst in winter.
Bacon notes that water is the principle of moisture — it is what makes bodies soft, pliable, fertile. Without water, the earth becomes dry and barren. Water is essential for life — all living things contain water and require it for their vital functions. Water is the great transporter — carrying nutrients to plants, carrying wastes away, carrying ships across the seas.
The comparison of water and air reveals the variety of nature’s operations. Both are fluids, but their properties are very different — air is compressible but water is not; water dissolves substances but air does not; water is heavy but air is light. These differences arise from the different Forms of these two substances — the different arrangements and motions of their minute particles. By studying both together, we can begin to understand the general principles of fluidity and the particular modifications that produce the specific properties of each fluid.
Experiments on the Growth and Development of Living Things
Bacon turns to the investigation of life — the growth, development, and reproduction of plants and animals. This is one of the most complex and difficult areas of natural history, but it is also one of the most important. The natural history of living things includes experiments on generation, nutrition, growth, reproduction, and decay.
The first experiments concern the generation of plants. Seeds contain the potential of the future plant — when planted in soil with proper warmth and moisture, they develop roots, stems, leaves, flowers, and new seeds. The growth of a plant from a seed is a process of development — the unfolding of a pre-existing structure, not the creation of something from nothing.
The second experiments concern the nutrition of plants. Plants take in water and minerals from the soil through their roots, and they take in air through their leaves. They convert these materials into the substance of their own bodies — wood, fiber, sap, fruit. The sun’s light is necessary for this conversion — plants grown in darkness become pale and weak.
The third experiments concern the generation of animals. Animals produce offspring through sexual reproduction — the male contributes seed, the female contributes egg, and the union produces a new individual. Some animals (like fish and insects) produce many offspring, while others (like elephants and humans) produce few. Some animals are born live, others hatch from eggs.
The fourth experiments concern the nutrition of animals. Animals take in food through their mouths, digest it in their stomachs, and absorb its nutrients into their bodies. Different animals eat different foods — some eat plants, some eat other animals, some eat both. The food is transformed into the substance of the animal’s body — into flesh, bone, blood, and other tissues.
The fifth experiments concern the growth of living things. Living things grow from small to large — a seedling becomes a tree, a infant becomes an adult. Growth involves the addition of new material, but also the organization of this material into the proper structures. Growth follows a pattern — each species grows in its characteristic way, developing the organs and parts that define its form.
The sixth experiments concern the life span of living things. Some plants and animals live only a few days, while others live for centuries. The life span is characteristic of each species — it is not a matter of chance but is determined by the nature of the organism. The life span is affected by conditions — good nutrition and favorable environment tend to prolong life, while hardship and disease shorten it.
Bacon observes that the phenomena of life are more difficult to investigate than the phenomena of non-living matter because life involves purpose and organization. A living thing is not merely a collection of parts — it is a system in which each part serves the whole. The heart pumps blood to nourish the body, the eyes see to guide the body, the brain thinks to direct the body. This teleological aspect of life makes it particularly resistant to mechanical explanation.
Nevertheless, Bacon insists that the same method of induction can be applied to living things. We must collect instances of generation, nutrition, growth, and reproduction, compare them, exclude what is not essential, and ascend gradually to the Forms of life. The Forms of life may be more complex than the Forms of heat or light, but they are still Forms — they can be discovered by patient investigation and systematic reasoning.
Experiments on the Human Body and the Senses
Bacon investigates the human body, focusing particularly on the senses and the operations of the mind. The natural history of man is the most important of all the natural histories, because man is the subject and object of all knowledge. By understanding the human body and the human senses, we can understand the limits and powers of human knowledge.
The first experiments concern the sense of touch. Touch is the most fundamental of the senses — it gives us direct contact with the physical world. Through touch, we perceive pressure, texture, temperature, and pain. The sense of touch is most acute in the fingertips and the tongue — these parts have the most nerve endings.
The second experiments concern the sense of taste. Taste is a kind of chemical sense — it detects the chemical properties of substances in the mouth. We distinguish between sweet, sour, bitter, salty, and savory. The sense of taste is affected by temperature and by the condition of the tongue — illness can impair taste.
The third experiments concern the sense of smell. Smell is also a chemical sense — it detects chemical substances in the air. The sense of smell is much more acute in some animals than in humans. Smell is closely connected with taste — much of what we call taste is actually smell.
The fourth experiments concern the sense of hearing. Hearing detects vibrations in the air — sound waves. The ear is a complex organ that concentrates and transmits sound to the inner ear, where it is converted into nerve impulses. Hearing can be impaired by damage to any part of this system.
The fifth experiments concern the sense of sight. Sight detects light — the most subtle and rapid of natural phenomena. The eye is a complex optical instrument — the cornea and lens focus light onto the retina, where it is converted into nerve impulses. Sight is the most informative of the senses — it gives us knowledge of distant objects, of colors, of shapes, of motion.
Bacon notes that the senses are limited. The eye cannot see objects that are too small, too distant, or too faint. The ear cannot hear sounds that are too faint or too high-pitched. The nose cannot detect chemical substances that are too dilute. The senses can also be deceived — optical illusions, auditory illusions, and other sensory deceptions show that the senses do not always report faithfully.
The limitations of the senses must be supplemented by instruments — telescopes extend the range of sight, microscopes reveal the invisible small, listening trumpets amplify sound. Instruments do not replace the senses but extend them — they bring the distant near and the invisible visible. The new philosophy must rely on the senses aided by instruments, not on the unaided senses alone.
The investigation of the human body extends beyond the senses to the passions and the operations of the mind. Bacon reports experiments on the effects of emotion on the body — how fear makes the heart beat faster, how anger makes the blood heat, how joy relaxes the muscles. The connection between mind and body is intimate — changes in the one produce changes in the other.
This investigation of the human body is crucial for the Baconian project because it grounds all knowledge in human capabilities. We can know only what our senses can detect — but by extending our senses with instruments, by correcting our senses with reason, and by combining our observations with those of others, we can know more than any individual could know alone. The new philosophy is human philosophy — it begins with the human condition and ends with human power.
The Scale of the Universe and the Place of the Earth
Bacon concludes the natural history with a consideration of the universe as a whole — the scale of the cosmos and the place of the earth within it. This section is not a complete cosmology but a collection of observations and experiments relevant to understanding the structure of the universe.
The first observations concern the size of the universe. The stars are at immense distances from the earth — so distant that their light takes many years to reach us. The sun is much larger than the earth — its diameter is many times the earth’s diameter. The planets are nearer than the fixed stars but still at great distances.
The second observations concern the motions of the heavens. The sun appears to move from east to west each day, and from north to south over the course of the year. The moon appears to move from west to east relative to the stars, completing a cycle in about a month. The planets have complex motions — they sometimes move forward, sometimes backward, sometimes stand still.
The third observations concern the nature of the celestial bodies. The sun is a source of light and heat — it illuminates and warms the earth. The moon reflects the sun’s light — it has no light of its own. The planets also reflect the sun’s light. The stars are self-luminous — like the sun, they shine by their own light.
The fourth observations concern the earth itself. The earth is round — as shown by the curved shadow it casts on the moon during eclipses and by the way ships disappear over the horizon. The earth rotates on its axis — producing the apparent daily motion of the heavens. The earth revolves around the sun — producing the apparent annual motion of the sun through the stars.
Bacon reports experiments that determine the circumference of the earth, the distance to the moon and sun, and the periods of the planets. These measurements are approximate but sufficient to give a scale of the universe — it is vast beyond human comprehension, and the earth is but a speck within it.
The consideration of the universe reveals the humility that the new philosophy requires. The earth is not the center of all things — it is a small planet orbiting a small star in a vast universe. The human senses cannot directly perceive the true scale of the cosmos — we must rely on reason and instruments to understand our place in the universe. But this humility is the foundation of power — by understanding the true nature of the universe, we can learn to act within it, to predict its motions, and to use its forces for human benefit.
Bacon ends the natural history with this perspective — the universe is vast, nature is complex, and human knowledge is limited. But the method of induction, the systematic collection of facts, the careful comparison of instances, and the gradual ascent to general laws — these give hope that human knowledge can grow without bound. The natural history is the foundation, but it is only the foundation — the work of interpretation remains to be done, and the Kingdom of Man lies ahead.
The Image of the Universe and the Doctrine of the Idols
Bacon provides a final summary of the natural philosophy that emerges from the Great Instauration — a picture of the universe as it appears when the mind is cleansed of the Idols and filled with the true knowledge of nature.
The universe, as revealed by the new philosophy, is a system of bodies and motions. All natural phenomena are produced by the motions of minute particles — the simple motions that constitute the alphabet of nature. These motions include the motion of expansion, of contraction, of aggregation, of segregation, of attraction, of repulsion, of rotation, of vibration, of undulation, and many others.
The Forms of nature are the laws that govern these motions — the rules according to which particles attract or repel each other, combine or separate, move in one way rather than another. To know the Form of a thing is to know the law that produces it — and to know the law is to have the power to produce or prevent the thing.
The universe is lawful — it operates according to fixed rules that can be discovered by patient investigation. There is no magic, no mystery, no occult force — only natural causes that can be understood and controlled. The universe is uniform — the same laws operate everywhere, on the earth and in the heavens, in the smallest particle and in the largest star. The universe is knowable — the human mind, though limited, can grasp these laws by the proper method.
Bacon also provides a final warning against the Idols — the false notions that still threaten the new philosophy. The Idols of the Tribe remain in the tendency of the human mind to find more order in nature than actually exists — to see patterns where there are only coincidences. The Idols of the Cave remain in the individual biases and preconceptions that each person brings to the study of nature. The Idols of the Marketplace remain in the confusions of language — the words that obscure rather than illuminate reality. The Idols of the Theatre remain in the false philosophies and mistaken methods that still have their followers.
The image of the universe that emerges from the new philosophy is not the final truth — it is a temporary picture, subject to revision as more facts are collected and more Forms are discovered. But it is a better picture than any that came before because it is based on facts rather than fantasies, on observation rather than speculation, on induction rather than deduction. The Great Instauration is not a completed work but a beginning — a foundation on which future generations can build, a method by which they can discover, a hope that they can realize.
The work ends not with a conclusion but with a call to action — the natural history is begun, the method is established, the instruments are prepared. What remains is the work itself — the patient accumulation of facts, the careful application of induction, the gradual ascent to knowledge, and the eventual achievement of the Kingdom of Man. The Great Instauration is not a book but a program — a program for the renewal of all learning, for the extension of human power over nature, and for the improvement of the human condition. Bacon has shown the way — it remains for others to follow.
