From the principle of bivolence it’s the same thing. You might try three valued logic but if you are using that why on earth didn’t you say?
No, no, I’ll stick to two valued logic here, don’t be afraid. I am a bit precise here: truths cannot be false per definition, otherwise it would not be truths. But I supposed you meant the same proposition can be true or false, so I prefer that formulation.
And on the thread about eternalism and presentism you were knocking Kkwan for trying precisely the same thing.
I more or less stayed away from that thread, Doug was so kind to take that over… I only made a few side remarks, not even aimed at kkwan. I suppose you mean another thread?
1) Certain sentences can be true or false
2) Truths could be false is a logical contradiction.
You are in error.
1, yes, 2 is as wrong as it can be. Maybe you mean “Truths are necessary true”?
If I say from some sentence that is true, then it cannot be false (according to me!). The sentence can turn out to be false, but then it was not a truth from the beginning. Where is the error? Or do you mean “I believe this to be true, but it turned out to be wrong”?
So the truth that you are married could be false, since you can’t be both married and a bachelor.
What is the difference between:
“The proposition that you are married could be false” and “the truth that you are married could be false”?
Introducing knowledge is to confuse epistemic possibilities with subjunctive possibilities, which I think is part of what’s causing you to make this error.
Sorry, I was just asking what you meant with ‘truths can be false’. The root cause of your misunderstanding lies somewhere else:
- Determinism says that given some state of (part of) the universe, on every point of time afterwards only one other state will occur.
- If I say ‘It is possible that a meteor will hit the earth’, I am expressing lack of knowledge.
So this would be an epistemic possibility. Right?
- If I say ‘It is possible that I decide I will go the seaside tomorrow’, again I am expressing lack of knowledge.
Now I have all knowledge I need: I know how to get to the seaside, I know the weather forecast, my family wants to go too. I only have to say ‘Yes, we go’, and it will happen. Here it becomes really interesting. It is possible that I’ll go to the seaside, isn’t it? From my own perspective it surely is possible, but is it an epistemic, or a subjunctive possibility?
And what from the viewpoint of the neurologist, who knows exactly what I will do, based on her remote sensing neurological mapping device?
Now my wife is the neurologist and sees me hesitating. She starts to discuss with me, in the hope she can change my mind. In what sense is it possible that we go to the seaside tomorrow?