Ludwig Boltzmann

The impossibility of an uncompensated decrease of entropy seems to be reduced to an improbability.

Let us consider a gas enclosed in a vessel. The molecules of the gas are in perpetual motion.

The initial state of the universe must have been one of very low entropy.

I think it is fair to say that the kinetic theory of gases is one of the most beautiful and most successful theories of physics.

The laws of probability applied to a large number of particles lead inexorably to the laws of thermodynamics.

We must not be surprised that in the course of time contradictions arise between theory and experiment; it is the resolution of these contradictions that leads to progress.

The theory that heat is motion is the key to understanding the second law.

The practical importance of the second law is greater than that of the first.

Mathematics is, in its way, the poetry of logical ideas.

The time variation of the distribution function is determined by collisions.

I am of the opinion, therefore, that the task of theory consists in constructing a picture of the external world that exists purely internally.

The assumption of atoms is so natural that one can hardly avoid it.

The entropy is a measure of the probability of a state.

The kinetic theory of gases has brought us closer to the ultimate constituents of matter.

One must not confuse what is improbable with what is impossible.

The hypothesis that gases consist of molecules in rapid motion is in agreement with all known phenomena.

The laws of thermodynamics, as empirically determined, express the approximate and probable behavior of systems of a great many particles.

A theory is the more impressive the greater the simplicity of its premises, the more different kinds of things it relates, and the more extended its area of applicability.

The increase of disorder (entropy) is what distinguishes the past from the future.

I feel like a fossil among the living physicists of today.