136 SCIENCE PROGRESS 



refusal of any success in resolving the perplexities of nature by referring to 

 the habits of the knowing mind the affirmation that " there is no absolute 

 physical reality which a mind may contemplate in its pure independence 

 of the contemplator and the conditions of its contemplation." i The role of 

 corpuscular theories of matter divides opinion concerning the function of 

 the knowing mind in science. Physical science has prospered in explaining 

 macroscopic aspects of nature by microscopic interpretations through particles 

 moving in void spaces, and, generally speaking, it has never prospered by 

 rejecting or ignoring corpuscular theories. Democritus established the 

 dominancy which the corpuscular concept was to secure and maintain 

 in interpreting physical phenomena. Descartes' protest against his con- 

 ceptions 2 was rapidly doomed to oblivion, and supplies one significant, 

 historical instance of the potency of corpuscular theories of matter and of 

 the impotency of rival conceptions in replacing them. The corpuscle, a 

 speculatively atten\:ated solid body, moving in interspaces, is the primary 

 model of the microscopic structure of matter which dominates the present-day 

 molecular and atomic theories. The extraordinary success of the atomic 

 theory since Dal ton, its power of collecting numerous and varied data under 

 systematising principles, its adaptability to new requirements as research 

 discloses fresh facts, its fertilit}^ both in explaining the old and in stimulating 

 discovery of the new, suggests that it is a real version of reality, essentially 

 independent of the mind or of its analogical route of interpretation from 

 the macroscopic to the microscopic. Gomperz suggests that, though the 

 atomic theory is still a fertile hypothesis, it may not even be the ultimate 

 truth at our disposal.^ The human mind may cling pertinaciously to the 

 corpuscle because it is so dominated by its primary models of reality. It 

 may be so habituated, by its fixed, relatively macroscopic position in reality, 

 to bodies separated by space and with some freedom to move in it, to " macro- 

 corpuscles," that it can only conceive more microscopic nature by looking, 

 as it were, as its daily vision of the world through the wrong end of a telescope. 

 It may be compelled to compare molecular or atomic systems to solar or 

 stellar complexes because its daily perceptions tie it firmly to its primary 

 analogical models. The siiccess, the persistence, the apparent incorrigibility 

 of the corpuscular conception may imply a determined, resourceful ingenuity 

 in applying an analogy to which it is psycho-physically restricted. If this 

 alternative estimate be true we cannot naively include corpuscular con- 

 ceptions in our " concept of nature " without noting that they represent a 

 mental procedure as well as an experience of nature. 



Descartes thought that matter is a plenum consisting " of closely packed 

 figures with plane surfaces, let us say cubes." When movement proceeded 

 in this plenum it " would cause the cubes to become spherical by gradually 

 wearing off the angles." But " the movement of the cubes cannot alter 

 their relative position without creating void," and " before the movement 

 alters the shape of the cubes by fracturing the angles it must cause their 

 displacement, and the slightest displacement destroys the plenum." * In 

 this Cartesian dilemma the rubbing away of angles represents an incipient 

 atomisation — the beginnings of a division of matter into separated corpuscles. 

 This incipient atomisation indicates the natural tendency of the human mind 

 to atomise matter — a tendency which can never be long or successfully 

 repressed. It seems to be a tendency imposed upon it by its familiar 

 " macro-corpuscular " vision of the world with which it begins its explora- 



^ Loc. cit., p. 23. 



2 Vide The Principles of Philosophy, trans, by Haldane and Ross, 

 Princ. 202. 



^ Greek Thinkers, Bk. Ill, ch. ii. 



* Carr, The General Principle of Relativity, p. 98, 



