lotka: efficiency in organic evolution 403 



There would probably be no difficulty in overcoming this 

 limitation of the Jevons' equation by introducing additional 

 terms into it. We shall not carry this out on the present occasion. 



6. Lastly, Jevons' equation is built up on a plan which seems 

 to involve the assumption that the individual is a perfectly 

 rational being, weighing all his actions and selecting some definite 

 course after having considered all avenues open to him and the 

 consequences to which they lead. 



In point of fact this is far from being the truth even for far- 

 seeing man. Not only are there many circumstances beyond 

 our ken which would enter into the determination of the actions 

 of a more perfect being, but even many of the facts plainly known 

 to the individual may fail to be weighed by him in framing his 

 actions, simply because no man can possibly have the entire 

 contents of his mind consciously before him at all times, or even 

 at any time. In other cases the individual may be aware of 

 certain remote consequences of his actions, but the lure of the 

 immediate gratification derived from such actions may so com- 

 pletely outweigh the promptings arising from a consideration 

 of remote consequences as to induce him to follow a course which 

 yields him a net result of pain rather than pleasure, loss rather 

 than gain. Indeed, nature tricks us into actions of this kind 

 to fulfil her own ends, which are to benefit the species, at the cost 

 of the individual if need be. 



Without going into details it may be suggested that this 

 limitation also is, in principle, at least, not as serious as at first 

 sight appears. 



In so far as it relates to the inability of the individual to fully 

 realize all the factors which might with advantage be taken into 

 account in framing his actions, it can probably be taken care of 

 under the heading of errors of observation, mentation, and 

 operation. 



On the other hand those errors which a man commits in giving 

 undue weight to immediate gratification when in conflict with 

 the prospect of more remote benefits these are plainly errors 

 of valuation and as such fall within the scope of the method here 

 developed. 



