Semiotics is a general theory of all existing languages... all forms of communication - visual, tactile, and so on... There is general semiotics... →
Umberto Eco
A theory can be proved by experiment; but no path leads from experiment to the birth of a theory.
Manfred Eigen
A theory has only the alternative of being right or wrong. A model has a third possibility: it may be right, but irrelevant.
In theory, there is no difference between theory and practice. But, in practice, there is.
I have just got a new theory of eternity.
Albert Einstein
An ounce of action is worth a ton of theory.
Ralph Waldo Emerson
Architecture doesn't come from theory. You don't think your way through a building.
Arthur Erickson
I wanted as little formal linguistic theory as I could get by with. I wanted the basic linguistic training to do a translation of the New Testament.
Daniel Everett
I would say that, intellectually, Catholicism had no more impact on me than did social theory.
Paul Farmer
It doesn't matter how beautiful your theory is, it doesn't matter how smart you are. If it doesn't agree with experiment, it's wrong.
Richard P. Feynman