Metaphysical Foundations of Natural ScienceImmanuel Kant

Kant published the Metaphysical Foundations in 1786, between the first and second editions of the Critique of Pure Reason, to show how the critical philosophy grounds Newtonian science. The work applies the categories of the Critique of Pure Reason to the empirical concept of matter, producing a priori principles for phoronomy (kinematics), dynamics, mechanics, and phenomenology.

Matter is defined as the movable in space. Kant argues that matter fills space not by mere presence but by repulsive force, balanced by attraction. These two fundamental forces make possible the density and division of matter, the transmission of motion, and the laws of impact. Newton's laws of motion receive a transcendental derivation: they are not merely observed regularities but conditions for the possibility of experiencing matter at all.

The work is technical and compressed. It matters because it attempts what no empiricist account of science can: to explain why the fundamental laws of physics hold necessarily rather than contingently.