When a ghostly sphere, containing memory and all ideas, has been distinguished from the material world, it tends to grow at the expense of the latter, until nature is finally reduced to a mathematical skeleton. This skeleton itself, but for the need of a bridge to connect calculably episode with episode in experience, might be transferred to mind and identified with the scientific thought in which it is represented. But a scientific theory inhabiting a few scattered moments of life cannot connect those episodes among which it is itself the last and the least substantial; nor would such a notion have occurred even to the most reckless sceptic, had the world not possessed another sort of reputed reality—the minds of others—which could serve, even after the supposed extinction of the physical world, to constitute an independent order and to absorb the potentialities of being when immediate consciousness nodded. But other men’s minds, being themselves precarious and ineffectual, would never have seemed a possible substitute for nature, to be in her stead the back-
