We know that time-binding capacity—the capacity for accumulating racial experience, enlarging it, and transmitting it for future expansion—is the peculiar power, the characteristic energy, the definitive nature, the defining mark, of man; we know that the mental power, the time-binding capacity, of our pre-historic ancestors, was the same in _kind_ as our own, if not in degree; we know that it is natural for this capacity, the highest known agency of Nature, to produce ideas, inventions, insights, doctrines, knowledge and other forms of wealth; we know that progress in what we call civilization, which is nothing but progress in the production and right use of material and spiritual wealth, has been possible and actual simply and solely because the products of time-binding work not only _survive_, but naturally tend to propagate their kind—ideas begetting ideas, inventions leading to other inventions, knowledge breeding knowledge; we therefore, know that the amount of progress which a single generation can make, if it have an adequate supply of raw material and be unhampered by hostile circumstances, depends, not only upon its native capacity for binding time, but also—and this is of the utmost importance—upon the total progress made by preceding generations—upon the inherited fruit, that is, of the time-binding toil of the dead; accordingly we know that the amount of progress a single generation can thus make is what mathematicians call an increasing function of time, and not only an increasing function but an increasing _exponential_ function of time—a function like _PR__T_, as already explained; we know, too, that the _total_ progress which _T_ successive generations can thus make is: _R/R-1_(_PR__T-P_)