Whenever anyone says, 'theoretically,' they really mean, 'not really.'

Everything is theoretically impossible, until it is done.

Faith means belief in something concerning which doubt is theoretically possible.

Theoretically, every probationary officer has a chance to become chairman.

Philosophy, which once seemed outmoded, remains alive because the moment of its realization was missed. The summary judgement that it had merely interpreted the world is itself crippled by resignation before reality, and becomes a defeatism of reason after the transformation of the world failed. It guarantees no place from which theory as such could be concretely convicted of the anachronism, which then as now it is suspected of. Perhaps the interpretation which promised the transition did not suffice. The moment on which the critique of theory depended is not to be prolonged theoretically. Praxis, delayed for the foreseeable future, is no longer the court of appeals against self-satisfied speculation, but for the most part the pretext under which executives strangulate that critical thought as idle which a transforming praxis most needs. After philosophy broke with the promise that it would be one with reality or at least struck just before the hour of its production, it has been compelled to ruthlessly criticize itself.

Metaphysics means nothing but an unusually obstinate effort to think clearly. The fundamental conceptions of psychology are practically very clear to us, but theoretically they are very confused, and one easily makes the obscurest assumptions in this science without realizing, until challenged, what internal difficulties they involve.

Whenever anyone says 'theoretically ' they really mean 'not really.'

Faith means belief in something concerning which doubt is theoretically possible.