Is counterfactual reasoning always faulty?
I understand that counterfactual reasoning is faulty is the sense that a TRUE consequent can’t follow from a FALSE antecedent.
e.g. If I was lizard then I would like flies
Nothing that can be said to be true could follow from “If I was a lizard” since it is not the case that I am a Lizard.
How can this be reconciled with counterfactuals propositions that take a tautological form in which case they must always be true.
e.g. If I was taller than you then I would be taller than you.
Is the above statement false because of its counterfactual nature or true because of its tautological nature? Or Is it neither?
How about a less purely tautological but still intuitively true statement like
If I was taller than you, then you would be shorter than I.
e.g. If I was lizard then I would like flies
Nothing that can be said to be true could follow from “If I was a lizard” since it is not the case that I am a Lizard.
How can this be reconciled with counterfactuals propositions that take a tautological form in which case they must always be true.
e.g. If I was taller than you then I would be taller than you.
Is the above statement false because of its counterfactual nature or true because of its tautological nature? Or Is it neither?
How about a less purely tautological but still intuitively true statement like
If I was taller than you, then you would be shorter than I.
Comments (12)
I think counterfactual thinking works in math. If x > 3 then it follows that x > 2 and if x > -5 then it follows that x > -15. There's a necessary logical connection required though between what the assumption is and what it entails.
I would also say that counterfactual thinking would never work in maths, in so far as the thinking was useful. I'm not sure about that either... This is all very new to me, so I could have it all wrong.
Classically, A=>B means that if A is true then B is true,and is equivalent to NOT A is True OR B is True.
Constructively, A=>B only means that a proof of B can be derived from a proof of A, and says nothing about the actual truth or provability of A or B.
The classical interpretation of material implication would say that you cannot be a lizard because you don't like flies, which shouldn't be problematic to assert, assuming that we live in a closed world containing a finite number of lizards that we can count in order to check their taste for flies.
But in the event we live in an open world containing a potentially infinite number of lizards, the classical interpretation runs into a problem in that the truth of A=>B can never be verified, implying that A=>B can never be asserted. And yet we do use conditionals without assuming that we live in finite closed worlds, which indicates our actual use of material implication is constructive rather than classical. For example, our definition as to what a lizard is includes the fact it eats flies, and therefore A=>B becomes somewhat tautologous.
Sorry, seems like I was barking up the wrong tree. Is a counterfactual exclusively a truth value state of the logical material conditional (false antecedent, true consequent). If it is then don't we encounter it every time we build a truth value table for a conditional statement in an argument?
How about if I say something like "If I am a lizard then I don't have gills"? The true consequent necessarily follows from the false antecedent. This is what I meant when I said there has to be a necessary logical connection between the falsity of the antecedent and truth of the consequent.
In a sense, it can be true and not faulty.
That is almost what logic is about.
There is an "understood" (the conditional) element:
(IF) a = b...
...and (IF) b = c...
...then a = c.
1. (adjective) Relating to or expressing what has not happened or is not the case
2. (noun) A counterfactual conditional statement
Quoting Nonsense
Not necessarily. Let's take your example: If I was lizard then I would like flies
A = I am a lizard
B = I like flies
C = A -> B (your example above)
Here both A and B are counterfactual, and therefore false. However, C - the counterfactual conditional statement - is true (at least that's the conventional interpretation).
Yes, that is exactly what I was doing. Thank you for pointing this out.
This was part of the issue. These concepts are new to me and I'm prone to thinking further ahead than my understating would permit. Leading me to err.
Thanks for the help.
I'm already quite far from where I want to be. You probably won't make it worse. Why not send the man lost and thirsty in the desert towards a mirage. Something is better than nothing, right?
Give the man a parable and send him on his way. At least that's better than giving him a counterfactual.