POSITIVISM.
Everybody in this room has, I suppose, heard of the "positive" sciences, or "Positivism" in some shape or other.
What does "Positivism" mean?
A system based on positive facts. But what are facts? They are (says the Positivist) observed phenomena. As for metaphysical conceptions of all sorts, these are negatives with nothing real, nothing positively true in them. Truth must be sought amongst observed phenomena.
It is worth our while to examine this last proposition. Take a "phenomenon." You have all observed colour,—what is it?
A physicist, if you ask him, will tell you of a modification in a ray of light variously produced—by refraction, for example—as when sunlight breaks a dark cloud into many-tinted beauty. But how if all the world of men and animals were blind?
The physiologist will step in and speak to you of the structure of the eye—the susceptibility of its retina for special impressions; there he says you may find colour.
Put both accounts together, and they appear as part-causes, each a factor helping to make up a result; which result physicist and physiologist would agree to call colour.
Yet again: Suppose the human and animal world were deprived of all consciousness, all which in the widest meaning we call mind—their eyes remaining like mirrors, telescopes, microscopes; perfect instruments, only every kind of intelligence, instinctive or rational, gone. Where would colour then be? The sun might play upon cloud or rain, the light of a rainbow be reflected in the eye. Were there but perceiving mind, the impression would exist. But we are supposing the impressible to be wanting; there is no sensation, no percipient; colour must remain unknown, for there is nothing capable of observing it.
Now this shows you, first, how important it is to emphasize the word observed added to phenomenon. It shows you, secondly, where the ultimate seat of every observation really lies; each observed phenomenon, each positive fact, is at last neither more nor less than a mental state. The evidence for each fact is the condition of your own mind, your consciousness as it is called. You may sift the thing witnessed, verify, examine, and cross-examine; but after all, your own consciousness is the first real evidence you have got.