THK PHTNC'IPLE OF LEAST ACTION, KTC. HI The principle has to-day at least two accredited champi Mach and Avenarius. 1 Mach has set it up as the fundamental principle of scientific thinking; Avenarius has claimed for it the leading place among the principles of Philosophy. I shall content myself with a brief attempt at estiraatin the real significance of these claims from our present point >!' view. We should note, in the first place, that we are no longer dealing with a tendency, but with a deliberately entertained scientific ideal, and we have to consider whether the principle of Economy can be considered as a principle of the L'nity of the Scientific Consciousness, and if so, in what precise sense. Now we may say that the activity of the Scientific Con- sciousness takes place mainly in one of two ways : either in the work of discovery or in the work of systematising what has been discovered. The work of discovery, according to Mach, must be in conformity with the principle of cumulative activity. The object must be given time to unfold itself before the observer, i.e., the observer must be continuously utilising his previous impressions of an object in order to penetrate more deeply into the meaning of the object : only in this way can the phenomenon exercise its full effect on the mind. This cumulative aspect of the principle of Continuity does not, however, impress Mach so much as the principle of Continuity itself. What he means by continuity may be gathered from the following extract : ' Once we have reached a theory that applies to a particular case we proceed gradually to modify in thought the conditions of that case, as far as it is at all possible, and endeavour in so doing to adhere throughout as closely as we can to the conception originally reached '. ' There is no method of procedure,' he adds, 'more surely calculated to lead to that comprehension of all natural phenomena which is the simplest, and also attainable with the least expenditure of mentality and feeling.' 2 So elsewhere he writes : ' The principle of Continuity, the use of which everywhere pervades modern inquiry simply prescribes a mode of conception which conduces in the highest degree to the economy of thought '. 3 Cf. H. Cornelius, Psychologic alx ErtaikmngHrineHteikafl, p. 84; cf. also William James, Principles of Psychology, vol. ii., pp. 183, 239, 240 ; cf. Text-hook of Psychology, pp. 844-345. 2 Mach, Science of Mechanics, p. 140 (translated by 3. McConuack). See also on this question Mach, ' The Economical Nature of Physics ' in a volume entitled Scientific lectures.
- 'Mach, id., p. 490.
