I don't think the article is implying "for no other purpose than fun". More like, for no other _apparent_ purpose than fun. > If we have convinced ourselves th

I don't think the article is implying "for no other purpose than fun". More like, for no other _apparent_ purpose than fun. > If we have convinced ourselves that rational explanation of action can consist only of treating action as if there were some sort of self-serving calculation behind it, then by that definition, on all these levels, rational explanations can’t be found. I think that this is one of the main point of the article - we can't simply explain away all of our behavior as some rational explanation. Not all play is merely for evolutionary adaption, and not all play has a purpose. Why does one puppy prefer to destroy a chew toy as play, and the other merely to squeak the squeaker?