Indeed, the need to occupy oneself with pure thoughts presupposes a long road that the human spirit must have traversed; it is the need, one may say, of having already attained the satisfaction of necessary need, the need of freedom from need, of abstraction from the material of intuition, imagination, and so forth; from the material of the concrete interests of desire, impulse, will, in which the determinations of thought hide as if behind a veil.