250 THE CASE AGAINST EVOLUTION 



instincts are simply metachronic chain-reflexes, in which one 

 elementary process releases another, each preceding phase 

 terminating in the production of the succeeding phase, until 

 the entire gamut of concatenated arcs has been traversed. 

 Hence, John B. Watson, the Behaviorist disciple of Loeb, de- 

 fines instinct as "a combination of congenital responses un- 

 folding serially under appropriate stimulation." 



But, if Darwinian anthropomorphism sins by excess, Loeb's 

 mechanism sins by defect, and fails to account for the indubit- 

 able variability of instinctive behavior. For, however fixed and 

 stereotyped such behavior may be, it manifests unmistakable 

 adaptation to external circumstances and emergencies, as well 

 as subordination to the general physiological condition of the 

 organism, phenomena that exclude the idea of fatal prede- 

 termination according to the fixed pattern of a determinate 

 series of reflex arcs. As Jennings has shown, synaptic coor- 

 dination in the neural mechanism cannot be more than a 

 partial factor in determining serial responses. The state of 

 the organism as a whole must also be taken into account. (Cf. 

 ^'Behavior of the Lower Organisms," p. 251.) Thus an earth- 

 worm may turn to the right simply because it has just turned 

 to the left, but this so-called "chain-reflex" does not involve an 

 invariable and inevitable sequence of events, since the earth- 

 worm may turn twice or thrice to the left, before the second 

 reaction of turning to the right comes into play. Any animal, 

 when sated, will react differently to a food stimulus than it 

 will when it is starved, by reason of its altered organic condi- 

 tion. We have something more, therefore, to reckon with 

 than a mere system of reflexes released by a simple physical 

 stimulus. 



The second type of variability manifested by instinct is its 

 capacity for complex and continuous adjustment to variable 

 environmental circumstances. Thus predatory animals, such as 

 wasps, crabs, spiders, and carnivorous mammals, accommo- 

 date themselves appropriately and uninterruptedly to the 

 changing and unforeseeable movements of the prey they are 



