Critique of Practical Reason and Other Works on Ethics

...possess sufficient data. Because of this unavoidable lack of precision, he did not enter his essay into the competition for the prize.

The same essay contained another very remarkable suggestion explaining why the moon always shows the same face to the earth. In fact, if the moon were originally in a fluid state, the tides produced in it by the earth (which would be very large) would have similarly slowed its rotation until the fluid surface reached a point of equilibrium in relation to the earth—that is original: i. e. (id est), until the moon rotated on its axis in the same amount of time that it took to orbit the earth. This theory has recently been presented as if it were a new discovery.

The hypothesis regarding the moon’s original fluidity was not an isolated thought for Kant; on the contrary, he spoke of it as part of a general theory of the heavens that he was preparing to publish. Accordingly, in the following year (1755), he published (anonymously) an important work of about 200 pages titled A General Theory of the Heavens; or, Essay on the Mechanical Origin of the Structure of the Universe, based on the Principles of Newton. This work is a detailed explanation of the Nebular Theory The theory that the solar system evolved from a mass of rotating gas or "nebula", which is commonly associated with the name of Laplace, even though Laplace’s System of the World original: Système du Monde was not published until forty years later (1796). The only major differences are: first, that Laplace assumes the condensation of scattered matter is the result of cooling; and second, that he takes an initial rotational movement for granted. In contrast, Kant believed he could explain both condensation and rotation using the two basic forces of attraction and repulsion. It is not easy to say whether Laplace—