directly, other organisms are altered, with consequent effects on the course of their accompanying souls. This account, which is true of my soul, holds good also with others. The world is such that we can make the same intellectual construction. We can, more or less, set up a scheme, in which every one has a place, a system constant and orderly, and in which the relations apprehended by each percipient coincide. Why and how this comes about we in the end cannot understand; but it is such a Uniformity of Nature which makes communication possible.[1]
But this may suggest to us a doubt. If such alterations of bodies are the sole means which we possess for conveying what is in us, can we be sure in the end that we really have conveyed it? For suppose that the contents of our various souls differed radically, might we not still, on the same ground, be assured of their sameness? The objection is serious, and must be admitted in part to hold good. I do not think we can be sure that the sensible qualities we perceive are for every one the same. We infer from the apparent identity of our structure that this is so; and our conclusion, though not proved, possesses high probability. And, again, it may be impossible in fact that, while the relations are constant, the qualities should vary; but to assert this would be to pass beyond the limits of our knowledge. What, however, we are convinced of, is briefly this, that we understand and, again, are ourselves understood. There is, indeed, a theoretical possibility that these other bodies are without any souls,[2] or that, while behaving as if they under-
