wouldn't that be incompetence?
I'll never forget an experience early in my airline flying career ... telling it to another pilot later ...
Ah that was a big day for you ... now instead of being incompetent because you didn't know any better ...
Now you do ... and you'll be held for negligence.
Incompetence and negligence often go together. The key distinction here is between "negligence" (which will get you criminally negligent homicide) and "recklessness" (which will get you manslaughter, which is more serious). Rather than give definitions, I'll give you hypotheticals to help explain the general difference.
First hypothetical - Let's suppose you go to a party and have a few beers. You're feeling a little "beautiful" but not really drunk, so you wait a little, have some water, take a piss, and decide to drive home, because you basically feel OK. While on the way home, you're just a little slower in your reflexes, and it's dark. You approach an intersection, don't appreciate that intersection quite as fast as you normally would, so you slam on the brakes but slightly cross into it and run over and kill a pedestrian who's crossing the street. Since you don't know a lawyer, you foolishly take a breathalyzer test. It shows you have a BAC of .081 - barely drunk, and you probably sincerely felt sober enough to drive. This would be criminally negligent homicide.
Second hypothetical - Let's suppose you do what a good friend of mine used to, which is the "Tour de Trudy's." As the Austinites here know, Trudy's is a Mexican restaurant in Austin that serves a somewhat famous Mexican Martini. They have a two-drink limit, because it'll **** you up. It's strong, tastes pretty good, and is pretty cheap for how much damage it'll do. My friend used to drive to all three of Trudy's locations in succession and max out on the martinis. He wasn't a very big guy, so downing six of those meant he was friggin' sloshed. Let's suppose that on the way home from the final location, he passes out at the wheel, his car jumps a curb and kills someone who's walking. Of course, he knows me and therefore knows better than to blow, but suppose that in his drunken stupidity, he forgets and does it anyway. He blows a .27 BAC. He was reckless and committed manslaughter.
Why the difference? The obvious answer is that my friend is much drunker, but that's an imprecise explanation. The big difference is my friend's inferred knowledge at the time he chose to drive home. The jury is going to infer that my friend knows he's slobbering drunk as soon as he takes the wheel. In fact, that's the whole point of the "Tour de Trudy's." They may not draw that inference in the first hypothetical. Accordingly, my friend knows that by driving home, he's taking a massive risk that he's going to inflict harm on someone else, and he's just choosing to disregard that risk for no reason other than to avoid the hassle and cost of calling a cab. (There was no Uber back then.)
Side note - These hypotheticals are for illustrative purposes, and I used them because they're easy to explain. They are actually ******** from a legal standpoint, because Texas has set DWI apart from other criminal laws to make it easier to nail somebody for something big if that person is driving drunk. They basically did it to "look tough," to virtue signal, and to appease crappy prosecutors who are too lazy to prove their case under the normal laws. Specifically, it has an "intoxication manslaughter" statute that effectively deems all drunk driving that causes a fatality to be manslaughter. Accordingly, even the guy in my first hypothetical could get charged with manslaughter because of this special rule. That doesn't mean he will for sure, but he can be.
