To Philosophise

Immanuel Kant, Introduction to Logic, tr. Thomas Kingsmill Abbott (London, 1885), p. 16:

Two things, chiefly, are required in a philosopher—1. Cultivation of talents and of skill, so as to use them for various ends. 2. Readiness in the use of all means to any ends that may be chosen. Both must be united; for without knowledge one can never become a philosopher; yet never will knowledge alone constitute a philosopher, unless there is added a fitting combination of all his knowledge and skill into unity, and an insight into the harmony of the same with the highest ends of human reason. 

No one can call himself a philosopher who cannot philosophize. Now, it is only by practice and independent use of one’s reason that one can learn to philosophize. 

How, indeed, can Philosophy be learned? Every philosophical thinker builds his own work on the ruins, so to speak, of another; but nothing has ever been built that could be permanent in all its parts. It is, therefore, impossible to learn philosophy, even for this reason, that it does not yet exist. But even supposing that there were a philosophy actually existing, yet no one who learned it could say of himself that he was a philosopher, for his knowledge of it would still be only subjectively historical. [...]

He who desires to learn to philosophize must, on the contrary, regard all systems of philosophy only as a history of the use of reason, and as objects for the exercise of his philosophical ability.

The true philosopher, therefore, must, as an independent thinker, make a free and independent, not a slavishly imitative, use of his reason. Nor must it be dialectical, that is, a use which aims only at giving to his knowledge an appearance of truth and wisdom. This is the business of the mere Sophist; but thoroughly inconsistent with the dignity of the philosopher, as one who knows and teaches Wisdom.