## Propositional Logic

• 26
Hello everybody!
So, I started learning about propositional logic a few days ago with the help of Stanford's introduction to Logic: http://intrologic.stanford.edu/notes/notes.html . I'm at chapter 4, Propositional Proofs, and I make sure to finish all the exercises at the end of each section in order that I see whether I have properly understood it.
I wanted to ask whether this is a good source material to learn Logic and whether it is not too sanguine to expect myself to understand it on my own given that I have no real background in mathematical reasoning.
Thank you

• 2k

Go for it. It looks really nice.

If you have questions, this is reasonable place to ask first. If the answers you get here aren't helpful, you can head for the logic StackExchange.

Quora is often a good place to find recommendations for other internet resources like classes posted on YouTube.
• 26

All right, thank you!
• 26
I have another question though. I'm learning logic for the sake of it; I love philosophy. Nonetheless, I'd like to know if learning logic will bring me any practical benefits, for example in verifying the validity of some arguments or stuff like that.
• 2k

Yes.
• 773
I'd like to know if learning logic will bring me any practical benefits, for example in verifying the validity of some arguments or stuff like that.
Hello.

I never learned pure abstract logic so I am a bit biased; but experience has shown me that nowadays, inductive reasoning is more needed than deductive reasoning. Deductive reasoning is logic and math, and we have computers and calculators for this. Inductive reasoning is finding definitions and principles, and I find this is usually the weak point of people's arguments. After all, a perfectly logical conclusion is only as strong as its premises.

That is not to say that logic is not important; just that people, while focusing solely on deduction, forget about induction.
• 26
Well, let's say that most of what I've been practising is just that, namely finding definitions and principles, whereas I haven't really paid much attention to, literally, the other side of the argument
• 225
It will definitely help you identify valid and invalid arguments - it probably won't help you much in identifying the sound ones amongst the former though. For that, as Samuel Lacrampe indicates, you'll need more than just the tools of deduction.
• 773

Gotcha. For most arguments, finding the validity of the logic is not too hard. A trick is to replace the complicated terms with simple concrete ones, and find sound premises with them.

Example: All A are B, some B are C, therefore some A are C.
Replacement: All triangles are shapes, some shapes are circles, therefore some triangles are circles.
This is not valid.
• 26

That's a useful trick! I'll try to apply it and see how well it goes
• 773

No probs.
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