Kant, Immanuel (1724–1804)

DOI: 10.4324/9780415249126-DB047-2
Version: v2,  Published online: 2004
Retrieved February 20, 2019, from

2. Kant’s work to 1770

In his first work, Living Forces, Kant tried to mediate a dispute about the measurement of forces between Descartes and Leibniz by employing a distinction between ‘living’ or intrinsic forces and ‘dead’ or impressed ones to argue that Leibniz’s measure was correct for the former and Descartes’s for the latter. This distinction could not be maintained in a uniform mechanics, and the young Kant remained ignorant of the mathematically correct solution, which had been published by D’Alembert in 1743. Nevertheless, the work already showed Kant’s lifelong preoccupation with the relation between scientific laws and metaphysical foundations. It also included the observation that the three-dimensionality of physical space is a product of actually existing forces, not the only geometry that is logically possible (10, 1: 24).

Kant’s works of 1755 reveal more of his originality and his enduring themes. Universal Natural History, deriving the present state of the planets from postulated initial conditions by reiterated applications of the laws of Newtonian mechanics, manifests not only Kant’s commitment to those laws, for which he was subsequently to seek philosophical foundations, but also his commitment to thoroughly naturalistic explanations in science, in which God can be the initial source of natural laws but never intervenes within the sequence of physical causes. New Elucidation, while not yet a methodological break from the rationalism of Leibniz, Wolff and Alexander Gottlieb Baumgarten (1714–62) (whose textbooks on metaphysics, ethics and aesthetics Kant used for decades), breaks with them on several substantive issues. Kant begins by rejecting Wolff’s supposition that the principle of non-contradiction is a single yet sufficient principle of truth, arguing instead that there must be separate first principles of positive and negative truths; following Crusius, Kant was always to remain suspicious of programmes to reduce all truth to a single principle. Kant then criticized previous proofs of the Principle of Sufficient Reason, although his own proof was also a failure. More importantly, he argued that the principle of sufficient reason does not entail the theory of pre-established harmony drawn from it by the Leibnizians: the need for a sufficient reason for any change in a substance proves the necessity rather than impossibility of real interaction among a plurality of substances. Transposed into an epistemological key, this argument was to become central in the first Critique. The work is also noteworthy for the first suggestion of Kant’s critique of Descartes’s ontological argument for the existence of God (see God, arguments for the existence of), and for a first treatment of the problem of free will as well. Here Kant defended against the indeterminism of Crusius the determinism of Leibniz (see Determinism and indeterminism), although he was later to criticize this as the ‘freedom of a turnspit’ (5: 97). Kant’s later theory of free will attempts to reconcile Crusius and Leibniz.

In the Physical Monadology (1756), Kant tries to reconcile the infinite divisibility of space in geometry with the need for simple, indivisible substances in metaphysics - the subsequent theme of the first Critique’s second Antinomy (see §8). Kant does not yet appeal to a metaphysical distinction between appearance and reality, but instead argues that because bodies in space are not ultimately composed of particles but of attractive and repulsive forces (1: 484), they may be physically indivisible even when space itself is still mathematically divisible.

Kant’s works of the 1760s introduce some of the methodological as well as substantive assumptions of his mature philosophy. The Only Possible Argument details Kant’s attack upon the ontological argument, the paradigmatic rationalistic argument because of its presupposition that an existence-statement can be derived from the analysis of a concept. Kant argues that ‘existence is not a predicate or a determination of a thing’ (2: 72), but rather the ‘absolute positing of a thing’ (2: 73); that is, the existence of its subject is presupposed by the assertion of any proposition, not inferred from the concepts employed in it. Kant also maintains that the other rationalist argument for theism, the argument from the contingency of the world to a necessary cause of it, as well as the empiricists’ favourite, the argument from design, fail to prove the existence of a necessary being with all the attributes of God. However, Kant still holds that the existence of God can be proved as a condition of the possibility of any reality. Finally, Kant further develops his argument that scientific explanation cannot allow divine intervention in the sequence of events, and that God must be seen only as the original ground of the laws of nature.

Negative Magnitudes announces a fundamental methodological break from rationalism. Inspired by both Crusius and Hume, Kant argues that real opposition (as when two velocities in opposite directions or a pleasure and a pain cancel each other out) is fundamentally different from logical contradiction (as between a proposition and its negation); he then applies this to causation, arguing that the real ground of a state does not entail its existence logically, but is connected to it in an entirely different way. This precludes any proof of the principle of sufficient reason from merely logical considerations alone (2: 202).

The Inquiry into the Distinctness of the Principles of Natural Theology and Ethics continues Kant’s attack upon rationalism. The question for this essay was whether metaphysics could use the same method as mathematics, which Kant firmly denied: mathematics, he argues, can prove its theorems by constructing its objects from their very definitions, but metaphysics can only use analysis to tease out the definitions of its objects from given concepts, and cannot construct the objects themselves (2: 276). The claim that the method of philosophy is analysis may sound like rationalism; however, Kant insists that in both metaphysics and ethics philosophy needs material as well as formal first principles, again precluding any purely logical derivation of philosophical theses. Kant does not yet have a clear account of material first principles - he is sympathetic to Crusius’s account of indemonstrable cognitions and to the suggestion of the moral sense theorists Shaftesbury and Hutcheson that the first principles of ethics arise from feeling, but not satisfied with either. Without yet naming it, Kant also introduces his distinction between hypothetical and categorical imperatives (2: 298).

Still in 1764, however, the book Observations on the Feeling of the Beautiful and Sublime already announces Kant’s departure from moral sense theory and introduces the most fundamental theme of Kant’s ethics. Virtue cannot depend merely on benevolent inclination, but only on general principles, which in turn express ‘a feeling that lives in every human breast and extends itself much further than over the particular grounds of compassion and complaisance…the feeling of the beauty and dignity of human nature’ (2: 217). In notes in his own copy of this work, Kant went even further, and first clearly stated his enduring belief that ‘freedom properly understood (moral, not metaphysical) is the supreme principle of all virtue as well as of all happiness’ (20: 31).

In Dreams of a Spirit-Seer, Kant ridicules traditional metaphysics by comparing it to the fantasies of the Swedish theosophist Emmanuel Swedenborg; Kant argues instead that metaphysical concepts cannot be used without empirical verification, and that therefore metaphysics can at most be ‘a science of the boundaries of human reason’ (2: 368). The work also contains further thoughts on morality, suggesting that the two forces of egoism and altruism define the structure of the moral world in much the way that the forces of repulsion and attraction define that of the physical world (2: 334). But Kant does not yet argue that postulates of practical reason may be a valid alternative to the delusions of metaphysics.

Finally, the brief essay on Directions in Space argues that incongruent counterparts, such as right- and left-handed gloves, which have identical descriptions but cannot occupy the same space, prove that the qualities of objects are not determined by concepts alone but also by their relation to absolute space. Kant did not yet raise metaphysical questions about the nature of absolute space or epistemological questions about how we could know it, but this essay can be seen as introducing the distinction between intuitions and concepts which was to be a cornerstone of Kant’s subsequent thought (see §5).

Citing this article:
Guyer, Paul. Kant’s work to 1770. Kant, Immanuel (1724–1804), 2004, doi:10.4324/9780415249126-DB047-2. Routledge Encyclopedia of Philosophy, Taylor and Francis,
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