Why do I venture to say that in the spiritual way we _ought_ to grow? And what in fact is that spiritual way? Do life and experience point out the way and emphasize the 'ought'? Here we come to the gist of our whole inquiry.
If in looking back along the road on which, in these chapters, we have been trying to pick out stage after stage, we discern a governing purpose and the foreshadowing of an end; and if we also discern not only the possibility but also the means, through intellect and intuition, through action and feeling and thought, of identifying ourselves with that purpose and throwing the energy of our own lives into furthering it, we shall see both the ought and the way. We shall dimly discern, too, the promise of the end, although we do not and cannot yet know what we shall be. From the moment when the life-current driving onward and overcoming one by one the reluctances of matter along the genealogical ascent to man, reached him—_homo faber_, the skilful tool-maker, _homo sapiens_, the able thinker—from that moment the sublime purpose of all that had gone before began to be revealed.
The advance of life's main stream in all its variety of operation shows, from the beginning until now, one character and motive-principle. It begins, as we have said, by subduing to its purpose the inveterate habits of material elements, those habits we speak of as physical necessity and law, raising their status that they may be servants in new power to a freedom foreign to themselves. From subduing and assembling elements within cells it passes to the assembling of cells and lifts up these in their turn to higher place. They play their part in a commonwealth; they are servants whose habits, like those of matter, further the cause of a freedom they cannot reach. Their own relative necessity is subdued and used through their coöperating. They promote what they neither see nor know. Finally they reach their highest function in a man's brain, where they coöperate to carry power to an incalculably various use. There it is that life, by a very splendour of new emancipation, passes, as the philosopher says, 'through the meshes of necessity,' passes through that net the cords of which it has itself both spun and knotted from the refractory substance of material things.