Note 148 — Chapter XXXVIII · THE METHODOLOGY OF SCIENCE (continued 3)

Kant’s attitude towards Newton’s absolute space is somewhat confused. At times he defends the absoluteness of space, making extensive use of the arguments of Newton and Euler. At other times he presents his own arguments in favour of the relativity of space and motion. Finally, in his last work (Metaphysische Anfangsgründe der Naturwissenschafften), he writes: “Absolute space is, then, necessary not as a conception of a real object, but as a mere idea which is to serve as a rule for considering all motion therein as merely relative.” How motion can be relative while space is absolute is a problem that Kant fails to elucidate. At any rate, the problem of the absoluteness of space and time in classical science refers not to the essence of space and time (a problem which would degenerate into one of metaphysics, hence which would be meaningless to the scientists), but solely to a discussion of those conceptions which are demanded by the world of experience. Hence we may realise that a man ignorant of mechanics is in no position to pass an opinion one way or the other. And Kant’s knowledge of Newtonian mechanics was extremely poor, to say the least.

Thus, in his Allgemeine Naturgeschichte und Theorie des Himmels, we find him giving incorrect formulæ for the most elementary facts concerning falling bodies. Then again, basing his arguments on what he claims to be the laws of dynamics, he tells us of a nebula which would set itself into rotation owing to its outer parts falling towards the centre and rebounding sideways against the inner parts. But this hypothesis is in flagrant opposition to the principles of dynamics, and had Kant spoken of a man pulling himself up by his bootstraps he would have given expression to no greater absurdity. Whereas this latter statement would violate the principle of action and reaction, Kant’s violates the invariance of the quantity of moment of momentum in a self-contained dynamical system.