Fitch proofs

Just use the logic rules.

Next time you need help with basic propositional logic go to >>>/adv/

>>8855014
Thanks will do!

>>8854798
I like logic so if you are able to coherently put that into something I can read without wanting to kill myself then I'll do the proof for you.

Preferably latex but using non-microscopic ink and having your picture aligned correctly will do.

I was going to help you but the picture is posted sideways. sorry bro

>>8854798
>some people here actually have to make an effort to learn the basics of propositional logic

lmao, thanks for the ego boost

>>8855735
I know I literally learned this the first day of my discrete math class

Fuck that baby logic garbage they teach to phil students. Learn some mathematical logic.

Just prove the Soundness and Completeness theorem for PL with a Hilbert deduction system (cause only Modus Ponens and not those billion other rules of inference) and appeal to truth tables for tautologies.

>>8855751

>baby logic garbage
>truth tables

wut

>>8855778
I mean doing derivations is annoying, to tell if a statement in PL is a tautology, truth tables are easy, then by soundness, that tells you there is a proof in your deductions system.

If you have some other super algorithm to tell whether a statement is a tautology I can do on paper in a couple minutes, I'm listening.

>>8855792

rules of inference can be derived from truth tables, and although they can be tedious, they are still better than doing out the entire truth table. Doing derivations quickly come with practice.

The problem with truth tables is that the number of rows increases exponentially with the number of variables (2^n), so it will take forever to do a truth table with say 5 variables.

>>8855811
I agree knowing how to syntactically manipulate formulas is important, but I think they should be justified by truth tables and the completeness theorem, not derivations especially in PL. Otherwise you're working with a crutch. An example, when we had to do derivations in FOL in an intermediate logic class, before we had the completeness theorem, some we couldn't just say, oh at this step we did contrapositive, or demorgan, we actually had to do it each time. It sucked, but once we had more tools those pesky parts of logic disappeared.

>>8855841
To quickly add on this, in the advanced logic class I used truth tables all the time to prove things, by taking all PL tautologies as axiomatic schema. Then if I wanted to use a formula in PL I would use a computer to tell me if it was a tautology. It was great.