"I'm not so certain of that, I can imagine a subtler form of force than magnetism. I can imagine the mind reacting upon matter, creating in its own right by the displacement and rearrangement of the molecules of a substance--say of wood. What is a wine-glass but an appearance? No, no! It will not do to be dogmatic. We must not assume too much. We must keep open minds. Are we not advancing? Is any one nearing the farther wall? No, my boy, each year should make us less arrogant. Ten thousand years from now men will still be discovering new laws of nature just as they were ten thousand years ago. It is childish to suppose that we or any other generation will know all that is to be known. Infinite research is before us just as infinite painful groping is behind us. I do not assume to say what the future will bring to mankind. Perhaps soon--very soon, science will shift its entire battle-line from matter to mind. To say the mind is conditioned in a certain way to-day does not mean that these conditions may not utterly change to-morrow. Great discoveries wait in the future." "But you would not say that a new way of squaring the circle would appear--or that perpetual motion--" "Oh no, no! Error is not a product of enlightenment. I only say that the problem which is insoluble to you and to me may be quite simple to the biologist of the twenty-second century. Once I thought I might come to know much of the universe, now I am quite certain I shall never know but a few processes--never the mystery itself." As the old man talked with the light of prophecy in his gaunt face, the young man's imagination took wing into the future, that mighty and alluring void, black as night, yet teeming with transcendent, potential unborn men and women, and his brain grew numb with the effort and his heart humble with the moments' prophetic glance. Ay, it was true! He in his turn would seem a child of the foolish past--a fond old man to the wise future. His complacence was lost. His faith in his authorities violently shaken. He recalled a line from Whitman: "Beyond every victory there are other battles to be fought, other victories to be won." And his eyes grew dim and his thought filled with reverence for those seers of the future, and with awe of the inscrutable and ever-beckoning and ever-retiring mystery of life.