Free will is what is examined: Necessity is what examines. Free will is content: Necessity is form.

It is only by the analysis of the two sources of knowledge, standing to one another in the relation of form and content, that the mutually exclusive, and separately inconceivable ideas of free will and necessity are formed.

Only by their synthesis is a clear conception of the life of man gained.

Outside these two ideas—in their synthesis mutually definitive as form and content—no conception of life is possible.

All that we know of men’s life is only a certain relation of free will to necessity, that is, of consciousness to the laws of reason.

All that we know of the external world of nature is only a certain relation of the forces of nature to necessity, or of the essence of life to the laws of reason.

The forces of the life of nature lie outside us, and not subject to our consciousness; and we call these forces gravity, inertia, electricity, vital force, and so on. But the force of the life of man is the subject of our consciousness, and we call it free will.

But just as the force of gravitation—in itself incomprehensible, though felt by every man—is only so far understood by us as we know the laws of necessity to which it is subject (from the first knowledge that all bodies are heavy down to Newton’s law), so too the force of free will, unthinkable in itself, but recognised by the consciousness of every man, is only so far understood as we know the laws of necessity to which it is subject (from the fact that every man dies up to the knowledge of the most complex economic or historic laws).

All knowledge is simply bringing the essence of life under the laws of reason.

Man’s free will is distinguished from every other force by the fact that it is the subject of man’s consciousness. But in the eyes of reason it is not distinguished from any other force.

The forces of gravitation, of electricity, or of chemical affinity, are only distinguished from one another by being differently defined by reason. In the same way the force of man’s free will is only distinguished by reason from the other forces of nature by the definition given it by reason. Free will apart from necessity, that is, apart from the laws of reason defining it, is in no way different from gravitation, or heat, or the force of vegetation; for reason, it is only a momentary, indefinite sensation of life.

And as the undefined essence of the force moving the heavenly bodies, the undefined essence of the force of heat, of electricity, or of chemical affinity, or of vital force, forms the subject of astronomy, physics, chemistry, botany, zoology, and so on, so the essence of the force of free will forms the subject matter of history. But even as the subject of every science is the manifestation of that unknown essence of life, yet that essence itself can only be the subject of metaphysics, so too the manifestation of the force of free will in space, and time, and dependence on cause, forms the subject of history, but free will itself is the subject of metaphysics.

In the experimental sciences, what is known to us we call the laws of necessity; what is unknown to us we call vital force. Vital force is simply an expression for what remains unexplained by what we know of the essence of life. So in history what is known to us we call the laws of necessity; what is unknown, we call free will. Free will is for history simply an expression for what remains unexplained by the laws of men’s life that we know.