Built Quote by Thomas Reid

We have reached a situation where a theory has been accepted as fact by some, and possible contrary evidence is shunted aside. [This is]…

— Robert Shapiro

How empty is theory in the presence of fact!

— Mark Twain

“What we have, in fact, is not a theory at all but a large collection of approximate calculations, together with a web of conjectures…

— Lee Smolin

Even theories must have foundations.

— Edgar Rice Burroughs

Any theory is better than no theory.

— Fuller Albright

Theory is worth but little, unless it can explain its own phenomena, and it must effect this without contradicting itself; therefore, the facts are…

— Charles Caleb Colton

No single theory ever agrees with all the facts in its domain

— Paul Feyerabend

A felicitous but unproved conjecture may be of much more consequence for mathematics than the proof of many a respectable theorem.

— Atle Selberg

The entire annals of Observation probably do not elsewhere exhibit so extraordinary a verification of any theoretical conjecture adventured on by the human spirit!

— John Pringle Nichol

Some theories are good for nothing except to be argued about.

— Georg C. Lichtenberg

There is a mask of theory over the whole face of nature.

— William Whewell

Theories can be based on any assumptions, however bizarre.

— Milton Friedman