106 THE EYE IN EVOLUTION 



duction, to animals was added a sensitive soul governing movement and sensation, 

 and to man a rational soul. But doubts occupied men's minds particularly in 

 the seventeenth and eighteenth centuries in the long disputation between the 

 materialistic French Cartesians who followed Descartes (1596-1650) and the 

 English Newtonians who were inspired by Newton (1642-1727) on the one hand, 

 and the mystic German Nature-philosophers on the other, the disciples of 

 Paracelsus in the classical tradition, who found philosophical expression in 

 Leibnitz (1646-1716) and Goethe (1749-1832). To the first the universe was essenti- 

 ally mechanical ; to the second not only living creatures but minerals and chemical 

 compounds were permeated by a directive vital force. A middle view was 

 represented by Lamarck (1744-1829) who claimed that the lowest organisms 

 were insensitive and that their conduct was completely governed by external 

 factors, driving forces derived from the environment ; but as the evolutionary 

 scale was ascended and a centralized nervous system was acquired, organisms 

 generated their own " sentient interieur " to a progressivly greater degree, thus 

 attaining an ever-increasing measure of self-determination until Vertebrates 

 were reached, at which stage intelligence became possible and ultimately found 

 its fullest expression in Man. Each of these views has been maintained in recent 

 times — the simple reflexology represented by Loeb (1918) and the Russian school 

 (Sechenov, 1863 ; Bekhterev, 1913 ; Pavlov, 1926-27) on the one hand, and 

 the purposive or "directive" psychology represented by Whitehead (1929), 

 McDovigall (1933) and Russell (1934-45) on the other, wherein vital force has 

 been replaced by the " general drive " of modern biologists, a state of tension 

 or action-energy which activates living organisms. Each view would find its 

 advocates today. 



The mechanistic view would place the emergence of visual reflexes 

 into the plane of consciousness as a late development. This attitude 

 found its apostle in Jacques Loeb (1906-18) ^ who considered that all 

 the orientating and instinctive reactions of the lower animals to light 

 or other stimuli were mechanically determined ; although in many- 

 cases it seems to respond voluntarily and often purposively, the move- 

 ments of the phototactic animal are those of a robot ; it is forced to go 

 where it is taken by its reflexly-driven cilia, legs or wings, an activity 

 in which consciousness or vision has no place. Even an ant with all its 

 proverbial intelligence orientates its journey to light unthinkingly as 

 does a sleep-walker or an automaton ^ and in this respect is as unteach- 

 able as a machine, completely totalitarian and incapable of individual 

 adjustment. 



It must be remembered that the new science of cybernetics has demonstrated 

 that similar reactions, sometimes of astonishing complexity, can be carried out 

 by non -vital mechanisms, those curious electro -mechanical first cousins of 

 computing machines, which by a combination of photo-cells, amplifiers, motors and 

 automatic governing devices, can simulate many of the reactions of living things, 

 not in appearance bvit in behaviour, as they navigate themselves around the 

 play-room of the electronic engineer (see Ashby, 1952 ; Walter, 1953 ; and 

 others). Such mock-biological robots, goal-seeking and self-regulatory, capable 

 of the storage of information and possessed of a rudimentary type of memory 



1 p. 28. 2 p (38_ 



