I'm amazed y'all are focusing on Batman's combat prowess when anyone who knows him also knows that straight up fights are not Batman's go-to. Violence for Batman plays into a) terrorizing his foes (which I think we can agree won't work on Goku who just plain doesn't scare easily) or b) as a last resort when all other options have failed. Yes, Batman *is* an impressive fighter, but that's not how he wins wars.
Batman has always been the World's Greatest Detective. He's a thinker and a shadowy manipulator. He is, essentially, what Lex Luthor would be if he was heroic, only coming to fisticuffs against a foe he knows for certain he has a way of beating in that manner. Goku, as a planet destroyer-level character, is far too strong for Batman to defeat conventionally, and Batman would recognize this fact presumably within mere HOURS of his prep period.
Batman knows he'd lose any straight up fight with Goku in short order. So there wouldn't be a
fight as Batman would play to his strengths and Goku's weaknesses, which is all in the realm of the mind. Goku's ego, combined with his naivete, is like a huge crack in his armor just WAITING for Batman to find and execute an exploit. Batman would resort to psychological warfare and tear Goku down that way, only then would he move in for the kill.
Batman stalks, he studies, he calculates, he plans, and
then he strikes.
To quote Rakker when he was talking about Superman vs Batman in 2007:
Remember, now, that Batman is more than just a man, even in comparison to Supes. Batman has transcended his humanity. The moment Bruce's parents were killed, so too was Bruce. It has been argued that Superman is the real man and Kent is the constructed identity, and I agree with that, but I contend that Bruce is also constructed. The millionaire playboy is an act, a mockery of humanity made to mask the terrifying darkness that is within. There is no Bruce, just as there is no Kent.
Batman is a nightmare.
Villains are afraid of him.
*Superheroes* are terrified of him.
Batman has made secret plans that detail how to take down every hero.
He is a thinker. A manipulator.
We all agree that he's smarter, but seriously, guys, next to Batman, Superman is a bloody dunce. I mean when opens his mouth to talk, Batman feels the room around him get stupider.
In this sense there would be no fight.
If Batman wanted to, the question is not *if* Batman would destroy Superman, it's *how.*
Whether it's Kryptonite, Magic, or his loved ones, Superman's weaknesses dangle out in the open, ripe for manipulation.
The god would be twisted, disassembled, and broken, emotionally and psychologically, with Batman never even coming into view.
Does anyone seriously think that Goku is immune to psychological warfare (which he is VERY not used to confronting)? Goku is used to straight up challenges, and the few times he's shown to deal with manipulative backstabby covert and in-the-shadows style antagonists who specialize in "ungentlemanly warfare", he's done so exceedingly poorly, frequently falling for traps and in general behaving EXACTLY the way his opponent wants him to.
He's gotten by such foes through sheer luck when he was a child or via being so powerful that no trap would matter as an adult, but Batman is on a whole different level from anything Goku has faced before. Goku's Ki detection won't work either as Batman's would just blend right into the background against everyone else's. And in a worst case scenario, because Ki is a natural force that ALL life forms possess, Batman would have no trouble learning how to harness it after some brief research, swiftly closing the power gap between them (Batman having trained to "Peak Human Potential", meaning he's as physically capable as any human could ever potentially be, easily edging out any human Z Fighter, and probably a few others) as much as is biologically possible to do.
Batman would also exploit Goku's character traits as a tactical advantage, as he postulated about a fight with Superman, in Batman #612:
If Clark wanted to, he could use his superspeed and squish me into the cement. But I know how he thinks. Even more than the Kryptonite, he's got one big weakness. Deep down, Clark's essentially a good person... and deep down, I'm not.
Now for my Devil's advocate section.Realistically, should a fight happen, I think Batman would ultimately yield the fight after determining that Goku isn't a threat to Earth. He'd continue to plan for the worst in the shadows, but he'd cede the present fight to Goku in the interests of keeping the Earth safe.