On Sentiments (Über die Empfindungen)
On Sentiments is a philosophical dialogue by Moses Mendelssohn. It belongs to the tradition of eighteenth-century German metaphysics and aesthetics shaped by Leibniz and Wolff, and it brings that tradition to bear on the question of what sentiment—sensory awareness or feeling—is and how it relates to pleasure, beauty, and moral life. The work is not a systematic treatise but a series of conversations among friends who examine philosophical questions through discussion, objection, and revision. Its arguments are presented dramatically, with positions emerging from the give-and-take of the interlocutors.
The dialogue opens with an inquiry into the nature of pleasant and unpleasant sentiments. The interlocutors begin from a nominal definition associated with Maupertuis: a pleasant sentiment is a representation that we prefer to have rather than not to have, while an unpleasant sentiment is a representation that we prefer not to have rather than to have. They soon identify an error in this definition. Our preference is often directed not at the representation itself but at the object it represents. We may disapprove of an evil and wish that it had never occurred; yet once it has occurred, and once it lies beyond our power to prevent or remedy, we may be strongly attracted to its representation. The distinction between the representation and its object is crucial: it explains why we sometimes seek out representations that are in themselves painful.
This distinction grounds the work’s central aesthetic contribution: the theory of mixed sentiments. The dialogue asks why we take pleasure in tragic drama and in representations of suffering, danger, and misfortune. Mendelssohn’s answer is that such pleasure arises from the perception of perfection—in the skill of the artist, in the virtue or dignity of the tragic figure, in the harmonious order of the whole—even when the object represented is imperfect or painful. The pleasure is mixed because it combines an objective imperfection (the suffering represented) with a subjective or formal perfection (the representation’s artistry and the soul’s activity in apprehending it). In this context, one of the protagonists distinguishes three kinds of pleasure: sensuous, beautiful, and intellectual. These correspond roughly to the three sorts of perception elaborated by Leibniz and Wolff—confused, clear, and distinct—and they mark out different levels at which the soul can take satisfaction in its representations.
The dialogue also develops an account of beauty. Beauty is characterized as the unity of multiplicity as apprehended by the senses: a manifold of sensory content is held together in a harmonious whole, and this unity pleases us. The beautiful is thus a perfection of sensory representation, distinct from the mere agreeableness of sensuous pleasure and from the intellectual pleasure of clear and distinct knowledge. The work considers how the fine arts imitate or idealize nature, and how the principles of beauty operate in poetry, painting, and music. These reflections belong to Mendelssohn’s broader project of showing that the senses have their own kind of rationality and that aesthetic experience is not merely subjective caprice but a mode of apprehending order and perfection.
The later conversations turn from aesthetics to metaphysics and ethics. The interlocutors discuss the existence of evil and suffering in a world created by a good and wise God. They defend a Leibnizian theodicy: evil is understood as privation or imperfection, and the universe as a whole is the best of all possible worlds. Human freedom is reconciled with divine providence through a conception of the will as a spontaneous power capable of acting in accordance with clear and distinct representations. The dialogue examines the nature of freedom, the compatibility of human agency with the divine plan, and the moral vocation of the soul. These discussions place On Sentiments within the broader Enlightenment debate over optimism, determinism, and the problem of evil.
The dialogue also addresses the immortality of the soul and the ethics of suicide. The interlocutors consider whether the miseries of life could ever justify taking one’s own life, and they weigh arguments against suicide drawn from the purposes of providence, the soul’s immortal destiny, and the moral order of the world. The prospect of immortality gives human existence a significance that makes self-destruction a violation of the divine order. At the same time, the dialogue acknowledges the force of the objection that life’s sufferings can seem unbearable, and it seeks to answer that objection through a rational account of the soul’s nature and destiny.
On Sentiments is an early and characteristic expression of Mendelssohn’s philosophical project. It combines aesthetics, metaphysics, and moral philosophy in a single conversational work, and it shows how the Leibnizian-Wolffian tradition could be adapted to address the problems of taste, tragedy, and theodicy. The theory of mixed sentiments developed in the dialogue became a central topic in eighteenth-century German aesthetics, and the work’s defence of rational pleasure in art helped to shape later discussions of the sublime and the beautiful. The dialogue’s engagement with Maupertuis, Leibniz, and Wolff situates it within the philosophical conversations of its time, while its literary form gives its arguments a dramatic immediacy that a systematic treatise might lack.
The conceptual core of the dialogue is the notion of mixed sentiment. A sentiment can be composite: a single representation may be pleasing and displeasing at once, because it presents both perfection and imperfection. This analysis is used to explain why tragic and sympathetic emotions can be pleasurable without denying the reality of suffering. The spectator’s displeasure at another’s pain is genuine, but it is taken up into a higher pleasure: pleasure in the perfection of the representation, in the moral greatness disclosed by the sufferer, and in the exercise of sympathy itself. The theory thus treats aesthetic response as cognitive and evaluative rather than as mere sensuous stimulation.
The dialogue extends this account into moral feeling. Approval and disapproval are understood as responses to perceived perfection and imperfection, so that aesthetic and moral sentiments are continuous while remaining distinct in their objects. Taste is presented as educable: by attending to harmonious wholes, the soul learns to discern order and to take pleasure in it. Artistic idealization is defended on this basis. The artist does not merely copy nature but selects and unifies, making perfection more perceptible; the beauty of art therefore manifests both the perfection represented and the perfection of the representation itself. This allows the work to treat the fine arts as a discipline of sensory cognition rather than as a merely decorative or dangerously seductive domain.
The metaphysical discussions are shaped by this aesthetic model. The world is considered as a whole whose perfection lies not in the absence of all contrast but in the harmonious ordering of diverse parts. Evil is not thereby called good; rather, the dialogue asks whether a rational and feeling spectator can approve a whole in which suffering has a place. Its optimism is both rational and aesthetic: it seeks to show that the universe can be loved as beautiful while its evils are acknowledged. The analysis of mixed sentiments thus connects the book’s aesthetics to its theodicy, since it explains how displeasure can be integrated into an approving response to a larger perfection.
The ethical themes are likewise bound to the account of sentiment and perfection. Freedom is treated as the will’s power to determine itself through representations of perfection, so that moral agency is compatible with providence rather than opposed to it. Immortality is considered as the horizon in which the soul’s moral and aesthetic vocation can be completed, and suicide is rejected because it severs the agent from that vocation and mistakes present misery for the final truth of existence. The dialogue’s form reinforces its content: philosophy proceeds through conversation, testing abstract claims against sentiment and experience. Its significance lies in making feeling a legitimate mode of philosophical insight, in giving “mixed sentiments” a central place in aesthetics, and in uniting taste, morality, and theodicy within a single conversational inquiry.
