Requested by RGF
To properly answer this question it must be stated aloud. “Why is a wise guy not a wise guy?”
Or perhaps the proper way of writing the question would be “Why's a whys guy not a wise guy?” In which case the answer is that a wise guy does not bother with so man “whys,” because he sees that “why” is only useful up to a certain point. Why allows one to make sense of how forces and agents operate within a system, but also comes to a terminus where continuing to ask “why” will only yield impotent “because” answers. Eventually one is bound to come to a point where the answer is “it just is” or “I just do,” and the “whys” guy who insists on asking why beyond the point of usefulness cannot be a “wise” guy who applies knowledge and understanding to his actions.
On the other hand, maybe this is all wrong and it is not a question at all, but a statement: “Wise: a whys guy not a Ys guy.” In this instance we have two types of men, the “whys” guy and the “Ys” guy. Y being typical shorthand for a “yes” response, especially in questionnaires, we can picture the “Ys” guy being the chap who does as he's told and doesn't bother with asking too many questions. He acts based on the vision of another and is not concerned with understanding too much of his own area of activity. The other man is the questioner – the “whys” guy – who will not act unless he has been given an explanation of the meaning and context of his actions. The statement declares the “whys” guy to be also “wise,” to the exclusion of the “Ys” guy.
Or perhaps it is the reverse! Perhaps this statement says that the “Ys” guy is “wise” while the “whys” guy is not! For what, after all, is wisdom except an aid in determining what actions one should take? And what is the critical foundation of society except a willingness to trust others and accept a certain level of blindness in order to function at greater levels than any single individual imagination would be capable of picturing? In this case, the “whys” guy slows society's progress, the “Ys” guy understands the value of endorsing a social structure – and is therefore “wise.”
And what else might these words be saying? “Why is a wise guy not a wise guy?” That is, asking why the wise are not wise? A bit a shoddy logic that illuminates the deeper truth that a wise guy is only wise in a certain context – that is, certain behavioral inclinations and certain maxims may make a man wise in one situation, and a fool in others. Put a wise debater in a managerial position and see the fool come out; ask the analyst to be an artist and you'll soon beg the fool to go back to his dungeon of spreadsheets!
And thus we see that the same bit of wordplay can be used to say this but it can also say that and that in this context we're discussing wisdom in the abstract and in that context we're discussing social structure, and no doubt there are more this and thats that might be appealed to as context. No doubt all this confusion could be avoided by multiplying words to create clear logical pictures of what we are trying to communicate, and therein lies the real wisdom of the statement: A bit of wordplay will stay with us far longer than logical clarity, for the wordplay resembles the obscurity that characterizes our lives as they are rather than our lives as our logical pictures say they can be.
But even that explanation pales in comparison to the goofy joy of playing with words!