God created… light anddark, heaven and hell—science claims the same thing as religion, that the Big Bang createdeverything in the universe with an opposite.“Including matter itself, antimatter.

— Dan Brown

BERENGER: And you consider all this natural? 

DUDARD: What could be more natural than a rhinoceros? 

BERENGER: Yes, but for a man to turn into a rhinoceros is abnormal beyond question. 

DUDARD: Well, of course, that's a matter of opinion ... 

BERENGER: It is beyond question, absolutely beyond question! 
DUDARD: You seem very sure of yourself. Who can say where the normal stops and the abnormal begins? Can you personally define these conceptions of normality and abnormality? Nobody has solved this problem yet, either medically or philosophically. You ought to know that. 

BERENGER: The problem may not be resolved philosophically -- but in practice it's simple. They may prove there's no such thing as movement ... And then you start walking ... [he starts walking up and down the room] ... And you go on walking, and you say to yourself, like Galileo, 'E pur si muove' ... 

DUDARD: You're getting things all mixed up! Don't confuse the issue. In Galileo's case it was the opposite: theoretic and scientific thought proving itself superior to mass opinion and dogmatism. 

BERENGER: [quite lost] What does all that mean? Mass opinion, dogmatism -- they're just words! I may be mixing everything up in my head but you're losing yours. You don't know what's normal and what isn't any more. I couldn't care less about Galileo ... I don't give a damn about Galileo. 

DUDARD: You brought him up in the first place and raised the whole question, saying that practice always had the last word. Maybe it does, but only when it proceeds from theory! The history of thought and science proves that. BERENGER: [more and more furious] It doesn't prove anything of the sort! It's all gibberish, utter lunacy! 

DUDARD: There again we need to define exactly what we mean by lunacy ... 

BERENGER: Lunacy is lunacy and that's all there is to it! Everybody knows what lunacy is. And what about the rhinoceroses -- are they practice or are they theory?

— Eugène Ionesco

The voices of actual communities are alive in a way no theory could every be even if, for now, it takes the form of tiny acts of resistance. Who doesn't cheat on taxes, avoid cops, or skip class? These acts themselves may not be revolutionary, but they begin to unravel the control from above. Anarchist approaches must be relevant to everyday experiences and flexible enough to address struggles in different situations and contexts. If we can achieve this, then we may thrive in the world after the dinosaurs. We might even be fortunate enough to be in one of the communities that have a hand in toppling them.

— Curious George Brigade

There ought not be two histories, one of political and moral action and one of political and moral theorizing, because there were not two pasts, one populated only by actions, the other only by theories. Every action is the bearer and expression of more or less theory-laden beliefs and concepts; every piece of theorizing and every expression of belief is a politcal and moral action.

— Alasdair McIntyre

Study, along the lines which the theologies have mapped, will never lead us to discovery of the fundamental facts of our existence. That goal must be attained by means of exact science and can only be achieved by such means. The fact that man, for ages, has superstitiously believed in what he calls a God does not prove at all that his theory has been right. There have been many gods – all makeshifts, born of inability to fathom the deep fundamental truth. There must be something at the bottom of existence, and man, in ignorance, being unable to discover what it is through reason, because his reason has been so imperfect, undeveloped, has used, instead, imagination, and created figments, of one kind or another, which, according to the country he was born in, the suggestions of his environment, satisfied him for the time being. Not one of all the gods of all the various theologies has ever really been proved. We accept no ordinary scientific fact without the final proof; why should we, then, be satisfied in this most mighty of all matters, with a mere theory?Destruction of false theories will not decrease the sum of human happiness in future, any more than it has in the past... The days of miracles have passed. I do not believe, of course, that there was ever any day of actual miracles. I cannot understand that there were ever any miracles at all. My guide must be my reason, and at thought of miracles my reason is rebellious. Personally, I do not believe that Christ laid claim to doing miracles, or asserted that he had miraculous power...Our intelligence is the aggregate intelligence of the cells which make us up. There is no soul, distinct from mind, and what we speak of as the mind is just the aggregate intelligence of cells. It is fallacious to declare that we have souls apart from animal intelligence, apart from brains. It is the brain that keeps us going. There is nothing beyond that.Life goes on endlessly, but no more in human beings than in other animals, or, for that matter, than in vegetables. Life, collectively, must be immortal, human beings, individually, cannot be, as I see it, for they are not the individuals – they are mere aggregates of cells.There is no supernatural. We are continually learning new things. There are powers within us which have not yet been developed and they will develop. We shall learn things of ourselves, which will be full of wonders, but none of them will be beyond the na.

— Thomas A. Edison

You have gone through enough theory, now it's time to take actions.

— Amit Kalantri

Theoretically speaking a good reader should also be a good learner, whatever the century and the place!

— Carl William Brown

Mankind has uncovered two extremely efficient theories: one that describes our universe's structure (Einstein's gravity: the theory of general relativity), and one that describes everything our universe contains (quantum field theory), and these two theories won't talk to each other.

— Christophe Galfard

The amount of understanding produced by a theory is determined by how well it meets the criteria of adequacy–testability, fruitfulness, scope, simplicity, conservatism–because these criteria indicate the extent to which a theory systematizes and unifies our knowledge.

— Theodore Schick Jr.

Since the beginning of physics, symmetry considerations have provided us with an extremely powerful and useful tool in our effort to understand nature. Gradually they have become the backbone of our theoretical formulation of physical laws.

— Tsung-Dao Lee