Philosophy 382
Bradford Skow


		
					Evolution and Altruism
					


Definitions:

	Trait T is an evolutionary altruistic trait =df. T is deleterious to the
	individual possessing it but advantangeous for the group in which it occurs. 
	(Sober 91)

	The fitness of a group of organisms =df. the average of the fitnesses of the
	organisms in that group.
	
	The fitness of trait T is frequency dependent =df. The fitnesses of 
	organisms with that trait depend on the frequency of that trait in the 
	group.
	
	
	
					
An argument that Altruism cannot evolve:

	
	1.	Altruistic traits are less fit than selfish ones.
	
	2.	Less fit traits decline in frequency.
	
	3.	Therefore, Altruistic traits will decline in frequency.
	
	

Sober claims that this argument has two readings:


	Reading 1:
	
	1. 	Altruistic traits are less fit than selfish traits within each group.
	
	2.	If A is less fit than S within each group, then A will decline in 
		frequency within each group.
		
	3.	Therefore, A will decline in frequency within each group.
	
	
	Reading 2:
	
	1.	Altruistic traits are less fit than selfish traits in the global 
		population.
		
	2.	If A is less fit than S in the global population, then A will decline in
		frequency in the global population.
		
	3.	Therefore, A will decline in frequency in the global population.
	
	
	
	
Definitions:

	D is an instrumental desire of S's =df. S only has D because satisfying it is a means to satisfying some other desire.
	
	D is an ultimate desire of S's =df. D is not an instrumental desire of S's.
	
	
	S is an extreme egoist =df. S's only ultimate desire is for his own welfare.
	
	S is a moderate egoist =df. S has an ultimate desire for someone else's
	welfare; but this desire is always outweighed by his selfish ultimate 
	desire when they conflict.
	
	S is an extreme altruist =df. S's only ultimate desires are for the welfare
	of others.
	
	S is a moderate altruist =df. S has an ultimate desire for his own welfare; 
	but this desire is outweighed by his desire for the welfare of others.
	
	
	Note: these definitions are all relative to a circumstance; S may be a
	moderate egoist in one circumstance but a moderate altruist in others.
	
	
	
	
	The emphathy-altruism hypothesis: empathizing with a needy other you see 
	causes you to have an ultimate desire for their welfare.


	The aversive-arousal hypothesis: seeing a needy other causes unpleasant 
	experiences. When we help, our ultimate motive is to make those experiences 
	stop. This is a motive directed at our own welfare. 
	
	(from sober and wilson, Unto Others, p. 261)



Sober's argument that we are moderate altruists:

	Two mechanisms causing us to care for our children:
	
	
	(A) We have an innate ultimate desire for the welfare of our children.
	
	(E)	We desire only our own welfare; but when our children are feeling bad,
		or are in danger, it causes us to feel bad.



	1.	If the ancestral population had both (A) and (E) available, then
		the more effective procedure is the one that is widespread
		in today's population.
		
	2.	The ancestral population had both (A) and (E) available.
	
	3.	(A) is the more effective procedure.
	
	4.	Therefore, (A) is the procedure that is widespread in today's 
		population.