The philosophy of life, then, can not be any mere absolute philosophy of reason. And as little can, or ought it to be purely and absolutely a philosophy of nature; not, at least, an exclusive one, that is, exactly such and nothing more. Such a philosophy of nature may, indeed, in its physiological aspect, possess unequaled scientific wealth, and be full of profound and ingenious thoughts. But still the right principles and the regulative ideas of human life can never be deduced from it easily, and without having recourse to forced constructions. For even man is, in his life, something higher than nature; even he is something more than a mere physical being. Still less possible, then, were it, from such a philosophy of nature, to derive, establish, and to render clear and intelligible the idea and being of God--the pervading reference to whom, however, makes man what he is. The idea of God deduced from such a source alone would, and indeed could only be, some great final cause of the system of nature.
Neither the conclusions of sound reason, and least of all those of the conscience--no, nor even dialectic itself (so far as it is profitably employed, by the knowledge of it being made available for the detection of error), nor physical science, when cultivated in a noble and lofty spirit, ought in any way to be excluded from the borders, or even the very domain of philosophy. On the contrary, she may, in her own peculiar way, adopt them all, and, giving them a more extensive sense and spirit, employ them for her own higher aims. In its primary and most essential respects, the philosophy of life is a thoroughly human science. It is nothing less than the cognition of man. Now, even on this account, and because it is only by means of his all-pervading relation to God that man stands above nature and is something superior to a mere physical being, and something higher, too, than a mere rational machine, therefore is the philosophy of life actually and in fact a true philosophy of God. The philosophy of life attains this high dignity beyond a mere philosophy of reason, or of nature, simply on this account--that the supreme life and the ultimate source of all other degrees of life is even God. Now this Supreme Life, which has its life in itself, is the subject of my present disquisitions. For it is even with the correct and complete notion of this Supreme Life that the Spirit of Truth first enters the human consciousness; and then, in the inner world of man, which before was "without form and void," that light begins to shine which never shall become darkness, and of which even this Spirit of Truth has said "that it was good." This divine but initiatory illumination is the first step in that progressive development of the internal light and truth in human life and consciousness, and which, as starting from this point and passing through its successive stages of advancement, it will be our object to trace in the last seven of the present Lectures. In the eight preceding disquisitions I have endeavored, by advancing step by step, to arrive at this last end of all. We have now reached the culminating point; and the Supreme Life, which, according to what has been already said, is the primary source of all other life, and which has life in itself, is now, together with the full and true notion of this life, to occupy our common consideration. And then again, descending from this summit of light and truth--for which, in the mean time, I entreat your entire and closest attention--I propose, with hasty step, to retrace our way through all the grades of man's spiritual enlightenment, to carry back your regards and mine into all the several spheres of life and consciousness.