Questions tagged [deduction]
The deduction tag has no usage guidance.
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deductive reasoning and first principle
In continuation of Are the concepts of reductionism and first principles the same? my next question is what is the relationship between first principle thinking and deductive reasoning ?
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Abduction, deduction and induction in medical diagnosis and intervention
(Apologies if my views on logical inference are overly simplistic -- I'm a radiologist by profession, very far from a philosophy major. My goal is to understand what medical decisions are and where ...
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What does it mean to say that two theorems (provable statements) are 'equivalent'?
sometimes one sees/reads assertions such as "[the bounded inverse theorem] is equivalent to both the open mapping theorem and the closed graph theorem", but taken formally and literally this ...
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rules of inference, language into metalanguage
There are rules of inference, e.g. in natural deduction they are listed.
These rules follow the same rules than the logic language.
If we see Modus ponens,
a → b, a ⊢ b
We can write for the same ...
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Proof of soundness of the rule of implication introduction in natural deduction calculus
From the definition of a sound calculus we can infer that a sound implication introduction has to have the form: Γ ⊢ A → Γ ⊨ A.
The rule for implication introduction goes (Γ ∪ {A} ⊢ B) ⊢ (Γ ⊢ A → B).
...
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I have taken my midterm exam 1 hour ago, and I am confused about some question meaning
1 what is the defferenece between "the justification of line 6" and "the application of xx on line 6"? For example, we can find that in the line 6, the application is wrong because ...
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abductive reasoning in many fields of study
In continuation of the discussion What is the relation between abductive reasoning and fallacy? my question is that if medical science judiciary history all uses abductive reasoning (almost all the ...
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Question about disjunction elimination in Fitch
I was recently using https://proofs.openlogicproject.org/ and realized that their version disjunction elimination is fairly restrictive.
I had a proof set up something like this:
p∨q (Premise)
p∨r (...
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Is backtesting inductive reasoning?
We do backtesting in finance; that is, we guess hypotheses/premises, and then use previous data to verify it.
Wikipedia
Investopedia
Is backtesting inductive or deductive reasoning? (Here we have ...
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Internal vs External Statement in Homotopy Type Theory
I would like to clarify the precise difference between the phrases "statement inside/ internal the theory" and "statement about the theory" in context of Homotopy Type Theory.
A ...
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Does the claim of an is/ought gap presuppose relevance logic (at least for morality-talk)?
Imagine Hume's remarks but with reference to the usual disjunction introduction:
In every system of conjunction, which I have hitherto met with, I have always remarked, that the author proceeds for ...
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Parmenides and deductions about existence
I am beginner in philosophy and have some problem following this paragraph:
"From the premise that something exists (“It is”), Parmenides deduces that it cannot also not exist (“It is not”), as ...
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Double-negation deduction rule in https://proofs.openlogicproject.org/
How can we use double-negation deduction rule?
For example, ~~p is the same as p.
I am not able to find how to eliminate ~~ in https://proofs.openlogicproject.org/
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Inference as tentative deduction
I've heard people make confident assertions about the categorical distinction between inference and deduction, but I'm not convinced.
I'm curious to hear rebuttals to the assertion that "...
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Modus Ponens false premises
I just started to get into deductive reasoning and was wondering how to prove an argument to be false.
In Modus Ponens:
If P then Q
P
thus, Q
If I had an argument like this:
P1) If you wear a tin ...
