A reply to a tremendously important post.
Premise 1: Agreed
Premise 2: Batman is one of the smartest–if not the smartest–mortals around (which is why I like him and Captain Comet best amongst heroes). But Superman comes from a tremendously advanced civilization with vastly augmented technologies and capabilities. Those technologies and capabilities come from the workings of the Kryptonian intellect, which likely outstrips the Terran intellect by multiple orders of magnitude. Even if we take into account the possibility that Kryptonian technological advances come from the fact that Krypton is eons older than Earth, and has therefore had more time to advance, any process of Kryptonian evolution, along with advances in intellectual capabilities that come from encountering the mental challenges of dealing with, and mastering new technologies–a Flynn Effect on Krypton, if you will, that results in a larger numbers of neural connections and faster-firing neurons in the Kryptonian brain that are the consequence of grappling mentally with the demands of a technologically advanced and challenging civilization–likely mean that even the smartest Terran is not as smart as the average Kryptonian. The Kryptonian brain has simply had to face more daunting challenges than the Terran brain has had to, and as a result, it is conditioned (over perhaps countless millennia) to be superior to the Terran brain. It is therefore a near certainty that Superman is smarter than Batman.
Premise 3: Agreed.
Premise 4 (Corollary to Premise 3): Agreed.
Premise 5: It is more accurate to say that Batman would never initiate a fight that he believed he could not win. But merely because Batman believes he can win a fight, does not mean that he will. Note also that–per references from my friend and colleague, Ben Domenech–there is something quixotic about Batman’s struggle, which indicates quite clearly that Batman is fighting a war he believes he might (will?) ultimately lose. Batman may fight irrespective of his pessimism, but that will be because he believes a larger issue is at stake. But his willingness to enter into a fight does not presuppose a prediction one can take to the bank stating that Batman will definitely win the fight.
Therefore, if Batman and Superman fight, it will be because Batman provoked the fight, perhaps believing that he could win, but perhaps believing instead that he will lose the fight, but that it is noble to carry it out. Even if Batman believes that he can win against Superman, it is not a certainty–by any stretch of the imagination–that he actually will. Given Superman’s augmented intellectual powers, superior strength, and vast array of superhuman abilities, absent the use of kryptonite (or magic used by an ally of Batman’s, to which Superman is tremendously vulnerable), followed by mortal blows to Superman’s person, Superman will likely win any fight against Batman.
Nota Bene: If we change the conditions of the competition, and ask which superhero pushed himself beyond the limitations of his species, Batman is the likely winner. Superman may well not be as talented or gifted as were other Kryptonians–largely because as a result of his planet’s annihilation, Superman has not had the opportunity to rigorously test himself and his capabilities against those of other Kryptonians, and has had to make do with laughably one-sided competitions between himself and Terrans. By contrast, Batman pushed himself relentlessly to be smarter, stronger, faster, quicker, and more knowledgeable than others of his species, in addition to acquiring and possessing a righteous sense of ruthlessness and purpose that gives Batman an additional massive edge in any battle against other Terrans. Between the two, Batman is very likely the supreme overachiever.