logical induction and deduction
Deduction
I have a Case, and a Rule, and I infer a Result
Case: Socrates is human
Rule: All humans are mortal
Result: Therefore, Socrates is mortal
nibli, ja'o (too often the longer equivalent .iseni'ibo), Resurrected Gismu idni
- Whence these strange definitions? They don't work for a vast array of interesting cases:
This or that. Not this Therefore that.
Socrates is human, Socrates is a philosopher, Therefore, Some philosopher is human
Induction
I have a Case and a Result, and I infer a Rule
Case: Socrates is human
Result: Socrates is mortal
Rule: Therefore, All humans are mortal
sucta, su'a, Resurrected Gismu usna
Objection:
Case: Socrates is human
Result: Socrates was a philosopher
Rule: Therefore, All humans are philosophers
To do good induction you need a lot of case-result pairs.
- This is more plausible in a way, but deals with only one type of induction and it the least useful. Statistical induction and causal induction are more important and don't fit this pattern at all.
Abduction
I have a Result and a Rule, and I infer a Case
Rule: All humans are mortal
Result: Socrates is mortal
Case: Therefore, Socrates is human
tolsucta, su'anai
Objection:
Rule: All tree frogs are mortal
Reslt: Socrates is mortal
Case: Therefore, Socrates is a tree frog.
i.e. Abduction is logically and scientifically silly; but as a (fallible) inferential mechanism it actually underlies much of human assumptions about the world.
- Well, this pattern certainly is, but the usual abduction (in this sense of the word)is fairly sturdy: If H held, T would occur; If H does not hold, T is pretty unlikely to occur, T occurs, Therefore probably H holds.
What about all the rest of the inference types tht logic deals with? Interpretation, analogy, evaluative, not to mention again the ones under induction? They and abduction, too, often get buried away in "induction" but here there seems to be some sorting out.