#Sensations not elementary.#
Professor Mach calls green, hard, etc., which in a certain relation are our sensations, "the elements of the world." These processes characterised as "green," "hard," etc., are in my opinion too special and at the same time too complicated to be considered elementary. I grant that they are elements of mind, because if further analysed, they cease to be mental phenomena. But they are not elements per se, not elements of the world. It remains doubtful to me whether Professor Mach understands by his term "sensation" only K κ and L λ or the whole relations A K κ, and B L λ. Taking it that he represents A B C … as both elements of the world and sensations, it almost appears certain to me that his term "sensation" stands for the whole process A K κ, and that he considers the scientific analysis of this process into A the outside thing, into K the nerve-vibration corresponding in form to the outside thing, and κ the feeling that takes place in experiencing the sense-impression A K, as an artificial procedure that serves no other purpose than that of familiarising us with certain groups of elements and their connections. The processes A K κ, B L λ, in that case would be considered by Professor Mach as the actual facts, while the A and B, the K and L, the κ and λ represent mere abstract representations without real existence, invented by scientists in order to describe the realities A K κ, B L λ, etc., with the greatest exactness as well as economy of thought. In their separate abstractness they are the tools of science only and we must not take them for more than they are worth.
#Thoughts as mental implements.#
If this be so, I understand Professor Mach very well and I agree with him when he looks upon all M and N with their respective μ and ν as being "noumena, Gedankendinge, things of thought." They are mental tools. Sense-impressions are realities, but mental representations are implements; they are auxiliaries for dealing with realities; they are "the augers and saws" employed in the different fields of cognition.
#Persistence of the elements of mind.#
Professor Mach says in his article "The Analysis of the Sensations": "When I (the ego) cease to perceive the sensation green, when I die, then the elements no longer occur in their customary, common way of association. That is all. Only an ideal mental economical unity, not a real unity, has ceased to exist." The term sensations, it appears to me, can in this passage be interpreted neither as K κ only, nor as the whole relations A K κ, but as any A B C … relations; and since Professor Mach has not excluded from them the element of feeling, I should have to represent them by A α, B β, C γ…. Sensations as I understand the term (viz. A K κ, B L λ), are elements of mind; if they are further analysed they cease to be mental states. Says Professor Mach: "If I close my eye (K) withdraw my feeling hand (L), A B C … disappear. In this dependence A B C … are called sensations." Should we not rather say, they cease to be sensations, if this dependence ceases? Accordingly, sensations and sense-impressions are for this and for other reasons not indecomposable, not ultimate atoms. The elements of mind can be further analysed into the elements of the elements of mind. The elements of mind do not persist; but the ultimate elements of the elements of mind, whatever they are, do (or at least may) persist.
When speaking of the elements of the elements of mind we cease to deal with objects of actual experience as much as a physicist or chemist does who speaks about atoms. Nevertheless the analysis is as legitimate in our case as it is in the chemist's. If in the above quoted passage I am allowed to replace Professor Mach's term "sensations" by elements of sense-impressions, I should not hesitate unreservedly to accept his idea. These elements of sensations would be all kinds of natural processes, all kinds of motion. They would be physical actions which are not mere motions but also and at the same time elements of feeling.
#Ideas as contrivances for comprehension.#
It is true that abstract concepts, and especially scientific terms and theories, are mere contrivances to understand the connections among, and the qualities of, real things. Ideas are not the real things, but their representations, and some ideas are not even representations; they are solely of an auxiliary nature and comparable to tools. They are used as working hypotheses wherever the real state of things is in part hidden from us, until we have found the actual connections. As soon as the actual connections are found we can and must lay down our tools.
In a certain sense all words and concepts are tools for dealing with the realities they represent. But some words are tools in a special sense. They have been invented for acquiring a proper representation.