James Clerk Maxwell

The concept of displacement current is essential for a complete understanding of electromagnetic phenomena.

The propagation of electromagnetic waves is a consequence of the interplay between electric and magnetic fields.

In every branch of knowledge the progress is proportional to the amount of facts on which to build, and therefore to the facility of obtaining data.

All the mathematical sciences are founded on relations between physical laws and laws of numbers.

The only laws of matter are those which our minds must fabricate, and the only laws of mind are fabricated for it by matter.

I have been battering away at Saturn, returning to the charge every now and then. I have effected several breaches in the solid ring, and now I am splash into the fluid one, amid a clash of symbols truly astounding.

Thoroughly conscious ignorance is the prelude to every real advance in science.

The aim of physical science is not the clear comprehension of things in themselves, but of the relations of things to our minds.

No theory of anything can be considered complete which does not account for the existence of atoms and molecules.

The 2nd law of thermodynamics has the same degree of truth as the statement that if you throw a tumblerful of water into the sea, you cannot get the same tumblerful of water out again.

We must therefore admit that the explanation of the phenomena of light is to be sought, not in the action of a medium, but in the properties of the ultimate molecules of bodies.

The vast interplanetary and interstellar regions will no longer be regarded as waste places in the universe...

The equations of dynamics completely express the laws of the historical method as applied to matter.

The human mind is seldom satisfied, and is certainly never exercising its highest functions, when it is doing the work of a calculating machine.

The theory of relativity is not a theory of principle, but a theory of construction.

The most obvious scientific lesson is the unity and simplicity of nature.

The agreement of the results seems to show that light and magnetism are affections of the same substance, and that light is an electromagnetic disturbance propagated through the field according to electromagnetic laws.

The energy of a material system is a function of its configuration and motion, and the total energy cannot be altered without the action of external forces.

I have been trying to get up a theory of electricity, but I have not yet got it into a form I am satisfied with.

The nature of heat is such that it tends to diffuse itself, and thus to pass from hotter to colder bodies.