Moses Mendelssohn’s Jerusalem is a work of philosophical prose—part treatise on church and state, part defense of Jewish civil existence, part meditation on language, revelation, and the nature of religious community. Published in the late eighteenth century by a leading figure of the German Enlightenment, it takes up the question of how civil and ecclesiastical authority can coexist without crushing the freedom of conscience that both, in their better moments, exist to protect. The volume also contains the Morning Hours, a series of philosophical lectures on truth, illusion, and the grounds of human knowledge, which belong to the same intellectual project: the careful separation of what can be known from what must be believed.
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Mendelssohn opens by naming the central difficulty. The state and religion are two supports of social life, and the task of politics is to balance them so that they bear weight rather than press the foundation into the ground. People have divided the relations of social man into moral essences, assigning each its own territory, rights, and duties—but the boundaries remain imprecisely fixed. Now the church pushes its marker deep into the state’s land; now the state permits intrusions equally violent. When the two make war, mankind is the victim; when they agree, it is seldom except to banish a third essence—freedom of conscience—which knows how to profit from their disunity.
How the Case for Separating Church and State Unfolds
The Problem of State and Church
Mendelssohn opens by naming the hardest problem of social life: the relation between the civil and the spiritual constitution, between worldly and ecclesiastical authority. Politics must balance these two supports so they bear up society rather than press it down. People have divided the social man into moral essences, giving each its territory, rights, duties, power, and property—yet the boundaries stay imprecise. Now the church drives its marker deep into the state’s land; now the state permits intrusions just as violent. When the two make war, mankind is the victim; when they agree, it is seldom for anything but to banish a third essence—freedom of conscience—which knows how to profit from their quarrels.
Despotism, he observes, at least has consistency: grant all its demands and you know where you stand, though the calm it yields is the calm Montesquieu describes, a fortress at evening to be surrendered to the storm by night. The Roman Catholic constitution offers the same fearful security. Let freedom disturb that solemn equilibrium and dissolution threatens from every side—hence the confusion of the early Reformation, and the embarrassment of the reformers themselves when fixing how far reform should go. Even now church-law textbooks waver: the clergy cannot surrender their claim to a constitution, yet no one knows what it consists in; men want to settle doctrinal disputes without a supreme judge, appeal to an independent church without knowing where to find it.
Hobbes and the Exaggeration of Power
Thomas Hobbes lived when fanaticism, wedded to a disorderly love of freedom, threatened to overturn the whole constitution. Weary of civil unrest and drawn to quiet speculation, he placed happiness in calm and security wherever it came from, and found it only in the unity and inseparability of supreme power. Public welfare, he thought, was best served if everything—even the judgment of right and wrong—were subjected to the civil authority. So he presupposed that man by nature has a right to all he has power for, that the state of nature is a war of all against all, ended only when men renounce their right and power into a fixed authority, after which whatever it commands is right. Civil freedom he had no sense for, or wished annihilated rather than misused. To save freedom of thought he took refuge in a subtle turn: all right rests on power, all obligation on fear; since God infinitely surpasses the authority in power, fear of God binds us to duties that must not yield to any fear of authority. But this held only for inner religion; outward worship he wholly subjected to the state, and innovation in church matters without its authority became high treason and blasphemy.
Much truth lies at the bottom of Hobbes’s assertions; the absurd consequences flow from exaggeration, from love of paradox or the needs of his times. Natural-law concepts were not yet clarified, and Hobbes has the merit for moral philosophy that Spinoza has for metaphysics: his acute error occasioned investigation. Physical power has since been distinguished from moral power, force from entitlement, and these distinctions are now so bound up with language that the refutation of Hobbes seems to lie in common sense itself.
Dead Actions and Living Conviction
The state and religion, Mendelssohn argues, differ essentially in how they work. The state can be satisfied with dead actions, works without spirit, conformity in deed without conformity in thought; whoever does not believe in the laws must still act according to them once they are sanctioned. Religion knows no action without conviction, no work without spirit; religious actions without religious thoughts are empty puppet-play, not divine service. They must proceed from the spirit for their own sake and can be neither purchased by reward nor forced by punishment. All the support religion can give the state is teaching and comforting—conveying common-beneficial dispositions through divine doctrine, and raising up the wretch condemned to death through otherworldly grounds of comfort.
The state commands and compels; religion teaches and persuades. The state issues laws, religion commandments. The state has physical power and uses it; religion’s power is love and beneficence. The one abandons the disobedient and casts him out; the other takes him into its bosom and seeks to convert or at least comfort him even in the last moment of life. Civil society, as a moral person, can have rights of coercion and has received them through the social contract; religious society makes no claim to coercive right and can obtain none through any contract in the world. The state possesses perfect rights; the church only imperfect ones.
Duties, Contracts, and the Church’s Poverty
To illuminate this, Mendelssohn ascends to the origin, extent, and validity of contracts among men, warning that he may grow too speculative for some readers, who are free to skip what does not suit their taste. The system of duties has a double principle: the relation between humans and nature, which is moral philosophy, and the relation between creature and Creator, which is religion.
Two Kinds of Truth
Mendelssohn opens by sorting truths into two classes. Eternal truths—pure mathematics and logic—stand beyond even divine omnipotence, since God cannot make His own infinite understanding changeable. The general laws of physics and of spirits are different: they rest on God’s will and hold only insofar as they answer His holy purposes; His power could have instituted other laws and may permit exceptions where useful. Beside these lie temporal truths—historical facts, events that happened once at a particular point in time and space and can be thought true only from that point. All history is of this kind: antiquity narrated, never perceived by us.
Reason, Observation, and Testimony
The classes differ in how conviction is reached. Necessary truths rest on reason, on the unchangeable relation between concepts; whoever teaches them must not commend them to faith but bring them home to the pupil’s reason, analyzing concepts into their marks until the inner sense perceives their joints. Such instruction, as Socrates said, is mere midwifery—we put nothing into the spirit that is not already there. Truths of the second class require observation besides reason: we must experience, observe, experiment, then extract what is common from particular cases. Here much must be accepted on the authority of others, since no lifetime suffices to experience everything—though we distrust reports wherever the object still exists and the experiment can be repeated. The Siamese may trust the European report that water hardens and bears heavy loads, and even teach it in physics textbooks; but let life depend on it, and they would insist on their own experience.
The Evidence of History
Historical truths, by contrast, occur only once in the book of nature. They can be perceived only by those present when and where they happened; everyone else must rely on the narrator’s credibility, for the testified thing no longer exists in nature. Without testimony no historical truth convinces us; without authority the truth of history vanishes with the event itself. God, fitting means to ends, grants reason where necessary truth is at stake, the spirit of observation where a law of nature is to be known, and confirmed historical certainty where a historical truth must be preserved for posterity. Only historical truths does the highest wisdom teach in a human way—through words and writing, confirmed where needed by extraordinary things and miracles. Eternal truths, insofar as they serve man’s salvation, He teaches through creation itself and its inner relations, legible to all men, awakening the spirit He created rather than producing mere historical faith by miracles. Mendelssohn therefore denies that human reason is too weak to convince men of the eternal truths indispensable to happiness, or that God had to reveal them supernaturally. Those who say so deny God’s omnipotence or goodness on one side while praising it on the other—and their claim makes revelation itself necessary, leaving unexplained why the far greater part of mankind has always lived without it.
Signs, Language, and the Invention of Words
Abstract concepts, the argument continues, cannot be retained without sensory signs: the soul can separate features but cannot think them without attaching them to a sensible mark. Languages are built of such natural and arbitrary signs; without them a person scarcely moves a step beyond the senses. The invention of a word can matter greatly—whoever coined “Natur” made no small discovery, for it let his contemporaries shame the conjurer by reducing his apparition to a general law rather than a special voluntary cause. Likewise the discovery that air has weight lets us reduce the rising of liquids in Torricelli’s tube to the general law of weight. Not every scientific word is empty sound if it cannot be derived from earlier elementary concepts; it suffices that it designates a general property in its true scope. The phrase fuga vacui was censurable not as empty but as false—more general than the observation. Before Haller discovered irritability, many had noticed the phenomenon, but it vanished at once, undistinguished from neighboring appearances, until Haller lifted it out, perceived its generality, and named it; now every particular case must be reduced to that law.
From Hieroglyphs to Letters
Designation serves two ends: keeping concepts at hand for ourselves and communicating them to others. Audible signs suit communication, since the concepts are already present and the sounds come at will; but for recalling separated concepts the sign must offer itself unbidden, and visible signs, being lasting, have the advantage. The first visible signs were presumably the things themselves—the lion for courage, the dog for fidelity, the peacock for proud beauty; the first physicians carried live snakes to show they could make the harmful harmless. Images came next, then outlines, then a part standing for the whole, then heterogeneous parts composed into a meaningful whole: hieroglyphics. From there to alphabetic script seems a leap beyond ordinary human powers. That our letters are merely signs of sounds is groundless: to the deaf-born, writing designates things immediately.
Induction and the Degrees of Certainty
Mendelssohn closes the first lecture by pressing the question of how we pass from one appearance to another. When we repeatedly meet a flower that looks and feels like a rose, we expect the smell and taste of a rose as well; from the reality of one appearance we infer the co-reality of all the others habitually joined to it. This inference carries no mathematical or logical certainty—only the degree of conviction grounded in probability, which he names induction and promises to examine later. He tests a food that tastes of salt: others feel the same sensation, it looks like salt, shows salt’s structure under the microscope, dissolves like salt; when the chemical test confirms expectation, his conviction about the effect the remainder will have on his body grows with the number of experiments on similar bodies. From many agreements experienced, he expects similar agreement in similar cases, with more or less evidence according to the count of cases.
Cause, Effect, Ground, Force
The second lecture continues tracing the first source of our knowledge of actual things. Frequent succession of two appearances, plus the grounded presumption that they are connected, leads us to call the earlier the cause and the later the effect, convinced they can be joined in a logical proposition—that in the concept of the cause as subject something will be found making the effect comprehensible. That something, the mark in the cause from which the effect follows, is the ground; every effect is grounded in its cause. By the same grounds we conclude that two appearances accompanying each other must be subordinate to a third common cause, mediate or immediate.
He then sets out a threefold degree of knowledge. The animal expects similar outcomes in similar cases, but not from the same ground: mere association of ideas does in animals what experience does in common people and reason in philosophers. An animal fears a slanted surface, and repeated experience has so connected the ideas that the sight of the slant makes the idea of falling the liveliest, producing fear. Man is not merely ruled by the liveliest representation; he forms the general proposition that all heavy bodies slide down slanted surfaces, presuming with ground of truth that in the developed idea of a slant something makes the possibility of falling comprehensible. The philosopher adds knowledge of the ground from mechanics, drawing the proposition closer to pure rational knowledge.
In the animal’s fear lies a formal syllogism that can be raised gradually to pure rational truth. The minor premise—”this is a slanted surface”—is given by sight. Reason, however, finds much to develop: what if sight deceived us, as it often has? The frequent agreement of appearances justifies expecting the same appearance at every other distance, in different media, through different means of vision, and to touch and every other sense of living beings—in a word, that it actually is a slanting surface. Where so much agrees under varied circumstances, we conclude an external object containing the ground of this agreement. Philosophical knowledge adds nothing to common evidence except to give account, by the art of reason, of the right by which we conclude this—the modes of inference called induction and analogy.
The most thoughtless man is not merely ruled by the liveliest representation; he has separated out the experiential proposition about a slant, grounding it only on having seen it so often. From repetition he concludes connection and forms a general proposition used as major premise. If experience teaches that wedges split bodies and screws set them in motion more easily, these are single propositions used without further reflection. The philosopher traces knowledge further back, finding in these three propositions the same general laws of nature—gravity and communication of motion—modified by differences of figure. Regarding the modifications these laws suffer through the figure of slant, wedge, and screw, he explains them by geometric principles, the laws of the thinkable and unthinkable, and finds wedge and screw comprehensible from the same principle as the slant. From this side his knowledge is pure rational truth; he sees the connection between subject and predicate clearly, without relying on expectation from experience.
But the general laws of nature themselves—gravity and motion—we do not recognize so purely rationally as we recognize their consequences and modifications through the given figure. Sensory appearances and their agreement have led us to conclude an object containing their ground; this object we call body, but its known marks do not yet suffice to conclude a general gravity, or a force of motion, logically connected with it. The propositions “All bodies have gravity,” “All bodies have a force of motion communicable in this or that way”
The Dream at the Fork: Reason and Common Sense
The lecture opens as a dream. The narrator follows two figures down a road—one fantastically dressed with an enthusiast’s face and wing-like growths on his head—until they reach a fork and part, one hurrying right, the other fluttering left. An elderly matron appears and urges the wanderers to take courage, promising they will not go unguided. The two are named: Gemeinsinn, the common sense, and Anschauung, contemplation. They squabble over trifles, and if a traveler waits at the fork without following either, they return to have the dispute settled by the matron. Usually she sides with common sense, and contemplation yields; but sometimes, when right is plainly hers, the stubborn fellow laughs in her face, cracks a flat joke, and goes his own way. Asked her name, she answers that on earth she is called Reason—then a terrible noise interrupts: a crowd has gathered at Dame Reason’s dwelling, resolved to drive out both common sense and reason, and the narrator wakes in fright.
The Rule Applied to Idealism and Skepticism
Waking, the narrator keeps the dream’s rule. Whenever speculation carries him too far from the highway of common sense, he stops, looks back to his starting point, and compares the two guides. Experience shows right usually lies with common sense, and reason must speak very decisively before he abandons it—must show clearly how common sense strayed, proving its persistence mere obstinacy. Turned against the idealists, egoists, and skeptics who doubt the material world, their grounds do not compel assent; there is strong presumption that continued reflection will vindicate common sense. Their doubts do weaken proofs built on its testimony. The practical geometer suffers nothing if his objects are mere appearance, since he only explains appearances; but natural theology must conclude the objective existence of a being, and the agreement of all senses and all men does not remove the doubt with geometric rigor—it is not impossible that this shared testimony rests on a limitation common to all animal senses, and is mere deception.
The Second Method: From the “I Think” to God
The thorough philosophers therefore preferred a second method, which presupposes our own existence and leaves the idealists’ thorny ground untouched. Immediate sensation carries the highest evidence; the subjective as subjective admits no doubt; even the egoist must grant “I think, therefore I am.” From a changeable being’s existence one may infer an unchangeable, necessary one, and here subjective and objective coincide—what I immediately feel cannot be deception. The Spinozist objects that the material world is in substance eternal and unchangeable, only its form in us changing; this can be met under the first method, but far more evidently under the second. If I am changeable, opposed predicates must be simultaneously thinkable of me—”I stood” and “I sit”—and since time alters nothing in the material of cognition, only its relative goodness, the ground of change lies in perfection, not thinkability. Hence a simple path: from my own existence to an unchangeable being that freely produces this best.
The Necessary Being and the Charge of Fatalism
Where does the necessary being’s ground lie? In its inner essence, its possibility—it exists because it is thinkable; its non-being cannot be thought. From contingent things’ undeniable existence their dependence on a necessary, free cause follows, for what a cause produces through approval is an effect of will, and a will that hits upon the best from rational grounds is free choice. The speaker refuses to flinch when told this makes the voluntary itself necessary. He knows no other freedom, for man or Godhead, than the capacity to see, approve, and choose the best; a capacity to act against that cognition is a non-entity. Let it be called necessity or fatality, provided the distinction survives: blind necessity rests on truth and untruth, moral necessity on goodness and perfection. He admits compulsion of this kind even in God, and accepts the name fatalist. The necessary being must possess cognition, approval, will, understanding—all in highest perfection. The ground of the truth “I exist” lies not in the material of the concept but in relative perfection: my constitution whereby, under these circumstances, I could become the best—approved by a free cause that is itself not contingent.
The Two-Headed Hydra of Pantheism
The true substance, the argument continues, is the totality of all material and thinking beings, presupposing an all-encompassing Subject that thinks all with perfect clarity; without a spirit-world, corporeal things form no system, and limited spirits are fragments embraced by an unlimited one. Spinoza’s infinite world thus leads to a being infinite in power—and the dispute would be largely settled, were it not for Lessing’s imagined cry that refuting Spinoza is not refuting Spinozism.
The Ideal Ground of the Possible
The dialogue closes its treatment of possibility by refusing to let mere possibility masquerade as a predicate of real things. If possibilities were objective characteristics, every possible thing would have to stand alongside actual things as itself actual—an absurdity. The ideal existence of all possibilities instead resides in a thinking subject; a possibility nobody thinks is a true non-entity, and to speak of something distinguishable that no one distinguishes is to juggle contradictory words. From this the argument presses further: nothing real is merely thinkable, it must actually be thought by some being, for without being noticed there is no characteristic and without being designated no object is present. Every trait of a thing must be thought by some understanding with the greatest distinctness, completeness, and thoroughness.
The Proof from Our Imperfect Self-Knowledge
Turning to self-knowledge, the speaker grants that his own existence is undeniable, yet equally undeniable is that his actual existence includes characteristics he is not conscious of, and that even his conscious ones fall far short of the perfection they have in the thing itself. No limited being—nor the sum of all limited beings, finite or infinite in number—can recognize those characteristics in harmony with the thing; no truth is known in its highest perfection without the whole sum of truths being seen in the same measure. Hence an infinite understanding must exist, representing all possibilities as possible and all actualities as actual, and since insight cannot be without activity, infinite understanding cannot be without the most perfect will. The chain is then laid out: everything real is real in its entire completeness; to that completeness corresponds thoroughness of concept in some thinking being; and complete, thorough concepts belong only to a perfect understanding, which is never without a perfect will.
Descartes, Leibniz, and the Leap to the Necessary Being
A new lecture takes up a priori proofs. The concept of the necessary being, as developed earlier, might lead a bold thinker like Descartes to infer existence from mere possibility—proceeding from explanation to the truth that God exists without presupposing any actuality, not even one’s own. Such a step would be unprecedented, since inference otherwise moves only from possibility to possibility or actuality to actuality; its uniqueness is precisely the mark of the truth, for only one substance can be this being. Descartes substituted the infinite, most perfect being for the necessary one, and since existence is a perfection, concluded that the necessary must actually be present. Leibniz called him back: too hasty—reason should walk, not jump. First prove that the concept contains no mutually canceling characteristics. That gap can be filled: of the necessary being all realities in the highest degree are affirmed and all defects denied, and since all perfections are affirmative characteristics, nothing contradictory can be feared in their union.
Truth, Goodness, and the Standing of the World
The argument then asks whether it suits human short-sightedness to claim that what we must think as real is actually present. Much is gained if opponents concede that man must think a Godhead as present, for the whole system of human insight and action would then be won. But the author goes further: every thinking being, whatever its scope, must think the necessary being as actual, since the opposite is unthinkable in and for itself. The negative proposition contradicts its own subject and can be thought true by no thinking being; its opposite follows from positive thinking power and is objective truth. To assert a thing’s actuality through reason, its truth and highest goodness must be given—truth making it a thinkable concept, goodness making it a thing. Contingent beings have truth but are good only under conditions; when time and space make a thing the best somewhere and somewhen, it arises actually. The necessary being, perfect under all circumstances, is as necessarily actual as necessarily possible. In the divine understanding the contingent is necessary as concept but not as thing; when it becomes an object of divine approval, it becomes actual—God speaks, and it stands. It is no arrogance for the son of earth to infer the infinite from his finitude; as concept he has been an object of divine cognition from eternity, and as thing he received actuality when the conditions of time and space made him a worthy object of divine approval.
The Friend’s Marginal Remarks
Editorial notes close the volume: a thorough philosopher and friend of the author read these essays and shared remarks not to be withheld from readers. On disapproving deception, he observes that once we learn to judge distances by comparing feeling, the representations of sight and hearing are placed not in but outside our body—there at the boundary where inner and outer meet.
The argument rests on a distinction that Mendelssohn returns to again and again: the state commands and compels, while religion teaches and persuades. The state can be satisfied with dead actions—works without spirit, conformity in deed without conformity in thought. It may leave the citizen the right to judge the laws but not to act on his own judgment, since as a member of society he renounced that right, without which renunciation civil society is an absurdity. Religion knows no action without conviction, no work without spirit. Religious actions without religious thoughts are empty puppet-play, not divine service. They must proceed from the spirit for their own sake and can be neither purchased by reward nor forced by punishment. The state possesses perfect rights; the church only imperfect ones. Its power is love and beneficence; it takes the disobedient into its bosom and seeks to convert or at least comfort him even in the last moment of his present life.
From this follows a conclusion Mendelssohn presses hard: the church has no right to goods and property, no claim to contribution or renunciation. Its rights never conflict with ours, so no collisions can arise between church and citizen—and where no claims are to be decided, a contract is absurd. All human contracts could confer no right on the church to goods and property, since by its nature it can make no claim to any. The church’s rights are admonishing, teaching, strengthening, and comforting; the citizen’s duties toward it are an inclined ear and a willing heart. If the church has no property, who pays the teachers of religion? At most, compensation for loss of time may be granted, and to determine and grant this is a task of the state, not the church. The desire for wealth, readily indulged in other estates, in these men soon turns to avarice because it is so contrary to their calling. The psalmist sings: “Sacrifice and offering thou didst not desire; mine ears hast thou opened.”
The same logic governs convictions. Convictions admit no benevolence, suffer no compulsion. I cannot renounce any conviction out of love of neighbor, nor transfer a share in my judgment; nor can I claim a right over another’s convictions. The right to our own convictions is inalienable. Hence the least privilege granted to co-religionists is an indirect bribery; the least freedom withdrawn from dissenters is an indirect punishment. It is a wretched illusion when textbooks of church law insist on the distinction between reward and privilege, punishment and restriction—useful to linguists, but bringing only bitter mockery to the wretch who must lack the rights of humanity because he cannot say “I believe” where he does not believe. Fear and hope act on the drive of desire; grounds of reason on the cognitive faculty. Whoever would lead men by fear and hope to accept or reject doctrines grasps the wrong means. Whoever believes truth-examination can stand while rank and dignity await here and want and misery there deceives his own heart.
What form of government should be advised for the church? None. Who shall decide when disputes arise in religious matters? Whoever God has given the capacity to convince. What government where nothing is to be governed; authority where no one may be subject; judgeship where no rights and claims are to be decided? Neither state nor church are competent judges in religious matters, since members could grant them no such right by contract. The state must watch from afar that no doctrines spread with which public welfare cannot stand—doctrines like atheism and Epicureanism that undermine the ground of social happiness—but it may not convert any eternal truth into a law, nor any religious opinion indifferent to the state into a land ordinance.
The Athenian Sage and the Purpose of Religious Community
Against the objection that religious society is the exception—that by a higher law no society may exercise a right flatly contrary to its own first purpose—Mendelssohn cites a worthy clergyman of the city: to exclude a dissident from the church means forbidding a crown-wearer the apothecary. The essential purpose of religious societies is common edification: by the magic power of sympathy, truth is to be carried from the understanding into the heart, and sometimes dead rational knowledge is to be quickened into high sensations through participation. When the heart clings too much to sensual pleasures to heed reason, it should be seized by the shudder of mortality, inflamed by the fire of devotion, and learn to know joys of a higher kind. To turn away the sick man at the door—the one who most needs this medicine, and needs it more the less he feels the need—is wrong. The first effort should be to restore that feeling and call back to life the part of his soul threatened by cold gangrene.
More nobly acted that philosopher at Athens. An Epicurean came from his revelry, senses clouded by nightly lust and head wreathed in roses; he entered the Stoic lecture hall to procure in the morning hour the last pleasure of enervated voluptuaries—the pleasure of mocking. The philosopher lets him in unhindered, doubles the fire of his eloquence against the seduction of pleasure, and depicts the blessedness of virtue with irresistible force. The pupil of Epicurus listens, becomes attentive, casts down his eyes, tears the wreaths from his head, and himself becomes a follower of the Stoa.
Language, Revelation, and the Mosaic Constitution
A long middle stretch of Jerusalem turns to the philosophy of language and the nature of historical truth. Abstract concepts require sensory signs to be retained and recalled: the soul can separate features but cannot think them without attaching them to a sensible mark. Languages are composed of such natural and arbitrary signs, without which humans would scarcely differ from unreasoning animals. The invention of a word can be of great importance in the sciences—whoever invented the word “Natur” made no small discovery, since his contemporaries could then shame the conjurer by saying his trick was nothing supernatural but an effect of nature. Before Haller discovered the law of irritability, many observers had perceived the phenomenon itself, but it vanished at the first moment and did not distinguish itself enough from neighboring appearances to hold attention. Only Haller succeeded in lifting this circumstance out of its connection, perceiving its generality, designating it with a word.
From here Mendelssohn distinguishes two classes of truths. Eternal truths—pure mathematics and logic—are unchangeable even by God’s omnipotence, since God cannot make His own infinite understanding changeable. The general laws of physics and the science of spirits are subject to God’s will and unchangeable only insofar as they correspond to His holy purposes. Historical truths—things that happened at one time and perhaps never recur—must be elucidated through themselves or remain unintelligible; they can be perceived through the senses only by those present at the time and place. Everyone else must accept them on authority and testimony. Necessary truths rest on reason; one who would teach another must not commend them to his faith but bring them home to his reason, not cite authorities but analyze the concepts into their marks. The instruction we can give herein consists, as Socrates well said, merely in a kind of midwifery: we can put nothing into the spirit that is not already there, but can ease the effort of bringing the hidden to light.
Whenever it accords with God’s purposes that men be convinced of some truth, His wisdom grants them the fittest means. If it is a necessary truth, He grants the requisite degree of reason. If a law of nature is to be known, He gives the spirit of observation. And if a historical truth is to be preserved for posterity, He confirms its historical certainty and sets the credibility of the narrators beyond all doubt. Only with respect to historical truths does it seem fitting to the highest wisdom to instruct men in a human way—through words and writing—and, where confirmation by authority was required, to let extraordinary things and miracles occur in nature. The eternal truths God teaches in a manner more befitting the Deity: not through sounds and written signs intelligible here and there to this or that person, but through creation itself and its inner relations, legible and intelligible to all men. He confirms them not through miracles, which produce only historical faith, but awakens the spirit He created and gives it occasion to observe these relations of things, to observe itself, and to convince itself of the truths it is destined to know here below.
This is the ground of Mendelssohn’s defense of the Mosaic constitution. The ceremonial law does not compel belief; it binds action, and its purpose is to keep the great truths of religion alive through practice. Aaron and the golden calf serve as a case study in how providence draws advantage from transgression. The people spoke only of a divine being to lead them and take Moses’ place, believing Moses had abandoned his post. Aaron, unable to resist the crowd’s insistence, cast them a calf; to hold them to the resolve to worship not this image but the Eternal alone, he proclaimed a feast to the Eternal for the morrow. But on the feast day, amid dance and revelry, the mob voiced quite different words: “These are your gods, Israel, that brought you out of Egypt.” Now the fundamental law was transgressed, the nation’s bond dissolved. What harsh measures the divine lawgiver had to resolve upon to restore the unruly rabble to obedience. Yet what advantage God’s providence knew how to draw from this unhappy incident.
Heathenism, Mendelssohn observes, held more tolerable notions of God’s power than of His goodness. The common man takes goodness and placability for weakness; he envies another’s least preeminence in power, wealth, beauty, honor—but not in kindness, since attaining gentleness lies largely in his own power. Reflection is needed to grasp that hatred and revenge, envy and cruelty are at bottom nothing but weakness, mere effects of fear. Fear, joined with contingent, insecure superiority, is the mother of these barbarous dispositions; only fear makes cruel and implacable. Whoever is securely conscious of his superiority finds greater felicity in forbearance and forgiveness. But how far was heathenism from this refinement!
