Dissatisfaction at the end of every system, and its irrational motive.
Some are seized as with a sense of dissatisfaction and delusion when they arrive at the end of the philosophical system and at the result that there is no reality save the Spirit and no other Philosophy save the Philosophy of the Spirit; and they do not wish to resign themselves to accepting that and nothing else as Reality, although obliged to do so by logical necessity. A world beyond which there is no other seems to them poor indeed; an immanent Spirit, trammelled and far inferior by comparison with a transcendental Spirit, an omnipotent God outside the world; a Reality penetrable by thought, less poetical than one surrounded with mystery; the vague and indeterminate, more beautiful than the precise and determined. But we know that they are involved in a psychological illusion, similar to his who should dream of an art so sublime that every work of art really existing would by comparison appear contemptible; and the dreamer of this turbid dream, should not succeed in achieving a single verse. Impotent are those poets most refined; impotent those insatiable philosophers.
Rational motive: the inexhaustibility of Life and of Philosophy.
But precisely because we know the genesis of their psychological illusion, we know that there is in it (and there could not fail to be) an element of truth. The infinite, inexhaustible by the thought of the individual, is Reality itself, which ever creates new forms; Life is the true mystery, not because impenetrable by thought, but because thought penetrates it to the infinite with power equal to its own. And since every moment, however beautiful, would become ugly, were we to dwell in it, so would life become ugly, were it ever to linger in one of its contingent forms. And because Philosophy, not less than Art, is conditioned by Life, so no particular philosophical system can ever contain in itself all the philosophable; no philosophical system is definite, because Life itself is never definite. A philosophical system solves a group of problems historically given and prepares the conditions for the posing of other problems, that is, of new systems. Thus it has always been and thus it will always be.
In such a sense, Truth is always surrounded with mystery, an ascending to ever higher heights, which are without a summit, as Life is without a summit. At the end of one of his researches every philosopher just perceives the uncertain outlines of another, which he himself, or he who comes after him, will achieve. And with this modesty, which is of the nature of things themselves, not my personal sentiment; with this modesty, which is also confidence that I have not thought in vain, I bring my work to a conclusion, offering it to the well disposed as an instrument of labour.