Thinking (n.) is a process whereby an object is thought by making it into a thought, depriving it of its sensuous quality, and thus penetrating it. It is deprive it of that quality of its own which it had for itself in opposition to me.
Thinking (n.) is the dynamic carving out of a new content, accomplished through the labor of determinate negation.
Thinking (n.) is itself a kind of labour: the mind works, and work is what forms the mind.
Thinking (n.) is what distinguishes man from the beasts — feeling he shares with them, a trite truth that sentimental theologians must be reminded of.
Thinking (n.) needs habit too: unpractised or too-long-continued thinking gives you a headache, because even pure thought is a partnership of soul and body.