Famous quotes containing the words true and/or propositions:
“It is very rare that you meet with obstacles in this world which the humblest man has not faculties to surmount. It is true we may come to a perpendicular precipice, but we need not jump off, nor run our heads against it. A man may jump down his own cellar stairs, or dash his brains out against his chimney, if he is mad.”
—Henry David Thoreau (1817–1862)
“It has often been argued that absolute scepticism is self-contradictory; but this is a mistake: and even if it were not so, it would be no argument against the absolute sceptic, inasmuch as he does not admit that no contradictory propositions are true. Indeed, it would be impossible to move such a man, for his scepticism consists in considering every argument and never deciding upon its validity; he would, therefore, act in this way in reference to the arguments brought against him.”
—Charles Sanders Peirce (1839–1914)