[marliechiller]

Thats an interesting point but I think I'd have to disagree - purpose is very much constrained to concious design. Those traits were selected not for the purpose of swimming but merely due to the pressure of selection itself. In your example of flippers, the selection pressure is likely on mobility but the purpose of a limb is not mobility in and of itself. Would that make a flipper purposeless if moving over land?

[MattRix]

Those traits would be selected because being able to swim increases survival. The purpose is survival via swimming.

To put it another way, the fact that the inputs (mutations) are random does not mean the outputs have no purpose.

If I said “the purpose of eyes is to see”, would you really disagree with that?

Also, it is entirely possible for body parts to have multiple purposes, that is quite common.

[deltaonefour]

>purpose is very much constrained to concious design.

Not true. Natural selection can produce the same results as artificial selection. They are both effectively the same process where in one scenario the guiding hand is human and the other scenario nature is the guiding hand.

If both nature and artificial selection evolved a mechanism that is very specifically and efficiently able to do one thing and one thing only does it mean that the thing evolved has no purpose? No it doesn't.

Either way we're getting into a linguistic and philosophical argument on the meaning of the word "purpose." These are traps. Ultimately we begin arguing about the definition of an ambiguous word thinking that the argument is profound. It's like all those arguments about "What is life." Pointless, "life" is the word that is loaded and ambiguous; any debate of that nature is simply an argument about the intricacies of a vocabulary word.