Is it always permissible to speak of the extension of a concept, of a class? And if not, how do we recognize the exceptional cases? Can we always infer from the extension of one concept's coinciding with that of a second, that every object which falls under the first concept also falls under the second? (Gottlob Frege)

Is it always permissible to speak of the extension of a concept, of a class? And if not, how do we recognize the exceptional cases? Can we always infer from the extension of one concept's coinciding with that of a second, that every object which falls under the first concept also falls under the second?

Gottlob Frege

Related topics

class coinciding concept exceptional extension object second speak under falls

Related quotes

The sorrow for the dead is the only sorrow from which we refuse to be divorced. Every other wound we seek to heal - every other affliction to forget: but this wound we consider it a duty to keep open - this affliction we cherish and brood over in solitude.

Washington Irving

We must find new lands from which we can easily obtain raw materials and at the same time exploit the cheap slave labor that is available from the natives of the colonies. The colonies would also provide a dumping ground for the surplus goods produced in our factories.

Cecil Rhodes

To unfold the secret laws and relations of those high faculties of thought by which all beyond the merely perceptive knowledge of the world and of ourselves is attained or matured, is a object which does not stand in need of commendation to a rational mind.

George Boole

As individuals and as a nation, we now suffer from social narcissism. The beloved Echo of our ancestors, the virgin America, has been abandoned. We have fallen in love with our own image, with images of our making, which turn out to be images of ourselves.

Daniel J. Boorstin

It is necessary to mark the greater from the lesser truth: namely the larger and more liberal idea of nature from the comparatively narrow and confined; namely that which addresses itself to the imagination from that which is solely addressed to the eye.

J. M. W. Turner