Peirce, Charles Sanders

"We can never know whether our opinions are really true."

"The universe is composed of signs and nothing but signs."

"A man should live so as to carry himself with dignity."

"The reasonable man adapts himself to the world; the unreasonable adapts the world to himself."

"Every statement is a prophecy."

"Logic demands only that our conduct should be such as we should be willing to see universal."

"The business of life is for everyone to assume responsibility."

"Nature is a habit, and God is the ultimate habit."

"A question which cannot be answered by any conceivable observation is metaphysical."

"The elements of every concept enter into all judgments."

"An indefiniteness in the object may be an indefiniteness that lies in the object itself."

"Thought is action, and action is thought."

"The soul stands alone, and therefore must work out its salvation through itself."

"Every dynamical action depends on a continuous stream of thought."

"Life and learning are one and the same."

"The significance of an intellectual product is measured by its bearing on future thought."

"Uncertainty is the predominant character of modernity."

"A sign is in a conjoint relation to the thing denoted and to the mind addressed."

"Art ought to enrich the world with a new kind of character."

"The pragmatic maxim is only an application of the sole principle of logic."

"The ultimate test of the validity of any argument is the stability of the resulting practice."

"Self-control is the beginning of all virtue."

"Every inference partakes of the nature of induction."

"The security of a man's life depends primarily upon society."

"Ideas demand that we act upon them."

"The real world is nothing but the world as it affects us."

"Mind is the supreme evolutionary factor in nature."

"Every event in the world entails a fact about every other event."

"Inquiry is the struggle to achieve a stable state of belief."

"The sentiment of beauty is essentially a sentiment of fitness."