Logic

 personal anecdote

Back when I went to university, majoring in Computer Science, we had to take some courses in the humanities or social sciences departments, "to keep our minds from becoming too narrow".
One favorite was the "Logic" course offered by the Philosophy department.
It was astounding to see how people who are not of a mathematical bent had a really hard time with what seemed trivial to us.
For example, the teacher would say:
"Given that (1) Everything green sprouts flowers and (2) alligators are green, what conclusion can we draw?"
The class would explode "But that's not true! Only plants have flowers! My marker is green and will never flower!" and so on.
Or the teacher would say, "I told my son that if he behaved himself I would take him to the beach. He misbehaved, and we went to the beach. Did I lie?" and everyone would say "yes!" and "you're spoiling the brat!"
They could not detach from real-world knowledge and "sense" enough to view a statement as just an example of "All A are B" or "If p then q" and deal with it at an abstract level.

Needless to say, the few Natural Sciences and Engineering majors in the room had absolutely no difficulty going GIGO mode...

I'm not totally sure which mode of thinking is better, to be honest.

I wanna be in that class...Omg. I'm so jealous.

Of course, you still can't divide by zero or somehow conclude, or expect that b > c just because a > b and a > c.

That's a horrible example. In no way does it relate b and c, beside saying they're both less than a. Of course you couldn't expect b > c.

In my perception, logic is what makes sense to our brain

Logic is different for everyone though. I pose this scenario:

You turn into an alley on a street (for some reason lol), no one else is around. You see a man with a gun pointing his gun to another man on the floor who is unable to defend himself in the slightest. You have a knife in your hand for some reason, and could safely get behind the man with the gun and stab him.

Let's put three people, who are labeled A, B, and C into this scenario as the person with the knife, and the man with the gun/defenseless man remain constant.

Person A: "I'll stab the gunman in the heart, essentially killing him. It's the right this to do because I'm saving another man who is defenseless."

Person B: "I'll stab the gunman in the arm so he can't use the gun, but I won't kill him because it's immoral to kill."

Person C: "I'm not doing anything because I don't know the situation, so I'm just gunna walk out of this alley and get some dunkin donuts until it's safe to go home."

"Logically" they all believe they are doing the "right" thing. It "makes sense to their brains."

But...? Which one is right? "Logically" there must be one correct solution, no?