But now if the new kinds of scientific “thing,” the corpuscular and etheric world, were essentially more “true,” why should they have excited so much criticism within the body of science itself? Scientific logicians are saying on every hand that these entities and their determinations, however definitely conceived, should not be held for literally real. It is as if they existed; but in reality they are like coordinates or logarithms, only artificial shortcuts for taking us from one part to another of experience’s flux. We can cipher fruitfully with them; they serve us wonderfully; but we must not be their dupes.
There is no ringing conclusion possible when we compare these types of thinking, with a view to telling which is the more absolutely true. Their naturalness, their intellectual economy, their fruitfulness for practice, all start up as distinct tests of their veracity, and as a result we get confused. Common sense is better for one sphere of life, science for another, philosophic criticism for a third; but whether either be truer absolutely, Heaven only knows. Just now, if I understand the matter rightly, we are witnessing a curious reversion to the commonsense way of looking at physical nature, in the philosophy of science favored by such men as Mach, Ostwald and Duhem. According to these teachers no hypothesis is truer than any other in the sense of being a more literal copy of reality. They are all but ways of talking on our part, to be compared solely from the point of view of their use. The only literally true thing is reality; and the only reality we know is, for these logicians, sensible reality, the flux of our sensations and emotions as they pass. “Energy” is the collective name (according to Ostwald) for the sensations just as they present themselves (the movement, heat, magnetic pull, or light, or whatever it may be) when they are measured in certain ways. So measuring them, we are enabled to describe the correlated changes which they show us, in formulas matchless for their simplicity and fruitfulness for human use. They are sovereign triumphs of economy in thought.
No one can fail to admire the “energetic” philosophy. But the hypersensible entities, the corpuscles and vibrations, hold their own with most physicists and chemists, in spite of its appeal. It seems too economical to be all-sufficient. Profusion, not economy, may after all be reality’s keynote.
I am dealing here with highly technical matters, hardly suitable for popular lecturing, and in which my own competence is small. All the better for my conclusion, however, which at this point is this. The whole notion of truth, which naturally and without reflection we assume to mean the simple duplication by the mind of a ready-made and given reality, proves hard to understand clearly. There is no simple test available for adjudicating offhand between the divers types of thought that claim to possess it. Common sense, common science or corpuscular philosophy, ultra-critical science, or energetics, and critical or idealistic philosophy, all seem insufficiently true in some regard and leave some dissatisfaction. It is evident that the conflict of these so widely differing systems obliges us to overhaul the very idea of truth, for at present we have no definite notion of what the word may mean. I shall face that task in my next lecture, and will add but a few words, in finishing the present one.
There are only two points that I wish you to retain from the present lecture. The first one relates to common sense. We have seen reason to suspect it, to suspect that in spite of their being so venerable, of their being so universally used and built into the very structure of language, its categories may after all be only a collection of extraordinarily successful hypotheses (historically discovered or invented by single men, but gradually communicated, and used by everybody) by which our forefathers have from time immemorial unified and straightened the discontinuity of their immediate experiences, and put themselves into an equilibrium with the surface of nature so satisfactory for ordinary practical purposes that it certainly would have lasted forever, but for the excessive intellectual vivacity of Democritus, Archimedes, Galileo, Berkeley, and other eccentric geniuses whom the example of such men inflamed. Retain, I pray you, this suspicion about common sense.
The other point is this. Ought not the existence of the various types of thinking which we have reviewed, each so splendid for certain purposes, yet all conflicting still, and neither one of them able to support a claim of absolute veracity, to awaken a presumption favorable to the pragmatistic view that all our theories are instrumental, are mental modes of adaptation to reality, rather than revelations or gnostic answers to some divinely instituted world-enigma? I expressed this view as clearly as I could in the second of these lectures. Certainly the restlessness of the actual theoretic situation, the value for some purposes of each thought-level, and the inability of either to expel the others
