Michael

According to existential introduction: Q(a) ? ?xQ(x) (if John is bald then there exists at least one thing which is bald) And surely: ?xQ(x) ? ?x (if ...

I don't understand what you're trying to get at. Either there are rules of inference or there aren't. If there are then my argument is valid. If there...

I don't know. Regardless, unless you want to reject the accepted rules of logic, you have to accept that my argument is valid (and as you accepted the...

2 is an application of existential introduction. 4 is modus tollens. They're valid rules of inference. 2 is saying that if the proposition "it is rain...

Then we run into this issue: T(x) ? x is true (definition) 1. ?p: T("p") ? p (premise) 2. ?p: T("p") ? ?"p" (from 1, by existential introduction) 3. ?...

OK, but do propositions exist when nothing is said? Do propositions exist when nothing is thought? Does the existence of a proposition depend in some ...

The same could be said of idealism/anti-realism.

This sounds like Platonic realism. But then if they're "residents of human thought" then presumably they don't exist when not thought?

I'm not ruling out propositions, I'm questioning what it means for a proposition to exist. Do propositions exist when nothing is said? Do propositions...

You're not providing a meaningful account of what a proposition/truth-bearer is. Is it a physical entity? Is it a mental concept? Is it a Platonic Ide...

And what's a truth-bearer? A sentence, e.g. an utterance?

So which of them are you saying exist(s) when it is not raining?

I think that this is certainly questionable. What is a proposition? Is it a sentence, e.g. an utterance? So, if it is raining then the phrase "it is r...

The conclusion follows from the premise via valid rules of inference. If the premise is true then the argument is sound.

It's a valid inference from step 3. It's called modus tollens. p ? q ¬q ? ¬p In this case, q is ?"p".

This is the argument: 1. T("p") ? p (premise) 2. T("p") ? ?"p" (inference, existential introduction) 3. p ? ?"p" (inference, hypothetical syllogism) 4...

Your response has no bearing on the sentence you're responding to.

The proposition "it is raining" is true if and only if it is raining If the proposition "it is raining" is true then the proposition "it is raining" e...

Some food for thought: T(x) ? x is true T("p") ? p T("p") ? ?"p" p ? ?"p" ¬?"p" ? ¬p

Burying the lede with that quote.

Then it's a topic for another discussion, not this one. This is where you're misunderstanding Fitch's paradox. It isn't showing that if we reject the ...

What follows from the knowability principle being denied has nothing to do with Fitch's paradox. Assume that John argues that an omniscient God exists...

Then just reject the knowability principle. I don't understand the problem.

Also on this point, why does there appear to be the assumption that English grammar dictates (or at least reveals) facts about metaphysics? The realis...

I think you misunderstand Fitch's paradox. It is a reductio ad absurdum against the knowability principle. So, Fitch's paradox is literature that spea...

Then it's not clear what you mean by saying that if there is a model of a cup then there must be a cup. Are you saying that if there is a model of a c...

Neither idealism nor anti-realism deny this. It's a mistake to equate "real" with "part of an external material world." So I don't understand what rel...

To borrow the way you like to argue, I don't drive subatomic particles, I drive a car.

And nothing in this says that my car is to be understand as being the mass of subatomic particles that is causally responsible for my experiences.

Dream-cups are to dreams as real-cups are to waking experiences: objects found only within the mental phenomena. Dream-cups aren't whatever physical s...

Does a painting of a unicorn necessarily imply that there's a unicorn?

What am I referring to when I say "pass me the cup" when dreaming?

This might be like saying "I'm not reading about words, I'm reading about wizards" in response to someone arguing that there's nothing more to stories...

We know that one of these must be true, as per the law of excluded middle (and assuming for the sake of argument that we don't know whether or not the...

But there are two parts to proposition p: 1) "the box is empty" is true 2) we don't know that "the box is empty" is true If we know part 1) then we ca...

Because that's what the knowability principle says. If some proposition p is true then it is possible to know that proposition p is true, and in this ...

It does according to the knowability principle: if a proposition is true then it is possible to know that the proposition is true (p ? ?Kp). a) "the b...

It can be, e.g: https://gdb.rferl.org/773AC938-0334-4BCC-910E-0F78126BAFE0_w1071_s_d3.jpg

You should check out Boltzmann brains, because according to that M is much more complex than S(M):

See here for one such discussion we had.

Not according to many here.

Not that I know of.

A scientific realist will say that an electron is a mind-independent entity. A scientific instrumentalist will say that the mathematical model of an e...

In fact from this I'm pretty sure it follows that ?q(q ? ¬Kq), so we're back to the initial formalism.

And more explicitly:

Yes, which despite the term "realism" is instrumentalist (much like Putnam's "internal realism" is anti-realist).

1. (p ? ¬p) ? ¬Kp ? ¬K¬p 2. (p ? ¬Kp ? ¬K¬p) ? (¬p ? ¬Kp ? ¬K¬p) 3. (p ? ¬Kp) ? (¬p ? ¬K¬p) 4. q ? ?Kq (knowability principle) 5. p ? ¬Kp ? ?K(p ? ¬Kp...

One can be a scientific realist but an anti-realist/idealist about everyday objects of perception. Electrons and protons and photons explain why we se...

That doesn't work. p ? ¬p just means "p is true or p is false" and says nothing about what we know. For example: either my name is Michael or my name ...

It's not a contradiction to say "there is intelligent alien life but I don't know that there is." Such a statement is possibly true.