*The previous reviewer who stated that "you don't have to think about it very long to realize that free will can't exist in a deterministic [universe]" has apparently missed all of the philosophical work relating to "Compatibilism," which is the very idea that free will and determinism are not mutually exclusive.*
I assume the commenter was referring to the normal understanding of what free will constitutes. Compatibilist "freedom" is entirely deterministic. So I personally do not think it is accurate to say that compatibilism says that free will is compatible with determinism, or that they are not mutually exclusive. While the words may seem true on the surface, this is extremely shallow, since the compatibilist view redefines freedom so that it amounts to determinism. In that case, "compatibilism" really only shows that determinism is compatible with determinism, and who can doubt it?
Often philosophers get really bogged down in trying to solve a problem and give it a name that suggests a solution, when the concept itself offers no solution at all. In other words, when you redefine freedom to fit with determinism, you are not making free will compatible with determinism. You are just redefining words to make them fit and then giving it a fancy title which suggests that some sort of solution has been reached, when clearly it has not (as I suppose the previous commenter was suggesting). So to just say something about the compatibilism discussion seems like hand waving that does not really grapple with the problem (just as "compatibilism" doesn't really grapple with the problem).
Let me give you a few examples. A married person and a bachelor are mutually exclusive by definition. Suppose someone really wanted to show that they are compatible. Can it be done? I say, no. But what if one redefined "bachelor" to mean "not single", or "married"? Voila! Now bachelor and married are "compatible", how cool! Or suppose you want to make a circle compatible with a square. Can it be done? I suppose you could just file down to corners of the square until you get a circle, but would anyone then say that squares and circles are compatible? Hardly. Such semantic trickery might be satisfying to some philosophers desperate to make their view work, but it is not satisfying to me (and many others who just take the time to "think about it" as the other commenter apparently suggested). But what do we know, after all? We aren't philosophers, so we probably are not qualified to make such observations (at least not without being quickly dismissed with hand waving and the use of catch words like "combatibilism"). Just my 2 cents.