- DanielCC
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Re: Retorsion argument, first principles and non-classical logic
Ouros wrote:
But to say that they have to overthrow intuitive support assumes that intuition, or rather prima-facie "perception" is a good truth-tracking method in the first place. How would you even justify that?
Also, is it possible that the skeptic truly believe what he say, without deceiving himself? If so, how can that be the case, and how can we say which one, beetween him and you, is correct?
What would you propose as indubitable knowledge? If you say tautologies, it ultimately depends of the validity of the PNC, but its scope is, for you, a matter of subjectivity in the end, if I read you well:
If some propositions can be both true and false presumably there is some criterion for this. Propositions like ‘I exist’, ‘X PSR holds’, ‘God exists’ or ‘Universals are Abstract Objects’ do not seem like the sort thing that could fall under this - what would it mean for instance to say the PSR is both true and false.
That's a lot of questions. Sorry if it takes your time.
I am not sure what you mean so this response will focus on the first. No we do not have to justify something’s seeming to be the case - it’s the sceptic’s job to try to drive a wedge between appearance and reality (which historically they have attempted to do by a number of arguments with interesting results) - the sceptic cannot start with a presumption of guilt (this seems to confuse the sceptical project with Descartes’ project, which is to assume everything which can mislead does mislead).
The sceptic may well be correctly reporting their intuitions - in such cases though one normally appeals to widely shared intuitions (the sceptic can try to undermine this in various ways e.g. Hume’s giving an alternate explanation for our apparent belief in causation, but that’s down to them).
About the logic you need to give examples of situations where non-classical logic would constitute a defeater. Merely suggesting the epistemic possibility that it could complicate matters isn’t enough (likewise these forms of logic try to account for why and when such things will occur, which, if so read the end of your last post correctly, you disregard).
- FrenchySkepticalCatholic
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Re: Retorsion argument, first principles and non-classical logic
Hey, Ouros,
I think you're putting too much into these non-classical logics. So far, I've seen nothing really scary about "well, the law of excluded middle doesn't hold". Alright, what does it even mean? Does it mean that such a law is FALSE? If so, it's also true?
I take most of these logic to be a huge appeal to idealism and to divorcing yourself from reality, and I wouldn't spend much time into them. 
God bless,
FSC
- John West
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Re: Retorsion argument, first principles and non-classical logic
BV's argument doesn't depend on Kant's transcendental idealism, guys.
- seigneur
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Re: Retorsion argument, first principles and non-classical logic
Let's go over it again.
Now, given the advance of non-classical logic, where the law of excluded-middle or the law of non-contradiction can, at least that's what their proponents claims, be rejected on a certain domain.
*Does it mean that retorsion argument doesn't work? In any case, what does it imply for general metaphysics?
The answer to the question depends on the scope of the "certain domain" in the above paragraph. Does the "certain domain" touch metaphysics? We have no examples that it does, so the question has no basis.
*Or maybe I'm wrong, and that would just means that metaphysics principles are faillible; but then, again, we couldn't uses them without appealing to intuition, which is close to begging the question.
This conclusion also depends on the scope of the "certain domain". It's necessary to see an example how anyone does metaphysics by denying e.g. the law of non-contradiction.
The whole exercise looks like claiming that there's this tool I have therefore that other tool probably doesn't work, without considering properly what the tools are for. The tools could be for different domains.
You can't say that you have a nail gun, it hits nails one by one, and therefore fractions in math are wrong or fallible. A nail gun has nothing to do with math, has no effect on it. Similarly, when you deny the law of non-contradiction, you can't do metaphysics. Or maybe you can, but then please show the result and we'll see whose metaphysics is better in some respect, if any.
Also, this,
1) For doing metaphysics, your need to build from First Principles wich are certain.
2) For knowing what is a first principle, you need either intuition or retorsion.
3) Not intuition, because it's question begging for a skeptic.
The skeptic does not belong to #3, because we don't do metaphysics for skeptics. We do metaphysics for ourselves to see if we can make coherent sense of the universe. If the skeptic does not care about coherence, how is that my problem or a problem for my metaphysics?
Last edited by seigneur (4/05/2018 1:11 am)
- Miguel
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Re: Retorsion argument, first principles and non-classical logic
"Now, given the advance of non-classical logic, where the law of excluded-middle or the law of non-contradiction can, at least that's what their proponents claims, be rejected on a certain domain."
Bullshit. LEM and PNC are absolutely true.
Any denial or relativization of PNC is irrational to the core. We know PNC is true with 100% certainty. We could all become Cartesian skeptics this very moment, and still PNC would be undeniable. It is a direct insight into the nature of reality. Maybe the external world doesn't exist. Maybe we don't exist, not even as a res cogitans. But PNC is true. It follows directly from being -- the fact that there is something --, which we know to be true with complete, absolute certainty.
What happened is that when Boole formalized Aristotle, he had to represent laws of thought by syntactic rules, and then idiots started thinking that the laws of thought were nothing but syntactic rules of symbollic manipulation, and so they can do away with these rules or change them.
The "intuition" involved in the first principles it just the grasp of the clearest possible kind of self-evidence. It is absolutely true, and undoubtedly so. If someone denies PNC, they are caught up in serious mental/linguistic confusion. At that point one has to try and guide them into rediscovering the self-evidence of the laws of thought, but if they can't see it then it becomes pointless to argue with them; you cannot argue against madness. Madness is just that: madness. Insanity.
Dialetheists and those who deny a first principle like PNC are worse than eliminativists. Much, much worse. If you think the eliminativist position is crazy, you should know logical revisionism is 10x crazier.
Last edited by Miguel (4/05/2018 3:39 am)
- UGADawg
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Re: Retorsion argument, first principles and non-classical logic
Aren't non-classical logics fairly common in some kinds of work in computer science?
- DanielCC
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Re: Retorsion argument, first principles and non-classical logic
Dialetheists and those who deny a first principle like PNC are worse than eliminativists. Much, much worse. If you think the eliminativist position is crazy, you should know logical revisionism is 10x crazier.
I am surprised by this - dialatheists can offer criterion for where the PNC will not hold e.g. conflicts between different linguistic/proportional systems, and alleged instances of it not holding i.e. self-referential paradoxes like the Liar. There are no even apparent instances of consciousness being an illusion (due to the analytical absurdity of that statement).
- SapereAude
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Re: Retorsion argument, first principles and non-classical logic
Similarly, when you deny the law of non-contradiction, you can't do metaphysics. Or maybe you can, but then please show the result and we'll see whose metaphysics is better in some respect, if any.
Ever heard of Hegel?
Wikipedia: Central to Hegel's conception of knowledge and mind (and therefore also of reality) was the notion of identity in difference, that is that mind externalizes itself in various forms and objects that stand outside of it or opposed to it, and that, through recognizing itself in them, is "with itself" in these external manifestations, so that they are at one and the same time mind and other-than-mind. This notion of identity in difference, which is intimately bound up with his conception of contradiction and negativity, is a principal feature differentiating Hegel's thought from that of other philosophers.
Hegel cites a number of fragments of Heraclitus in his Lectures on the History of Philosophy. One to which he attributes great significance is the fragment he translates as "Being is not more than Non-being", which he interprets to mean
Sein und Nichts sei dasselbe
Being and non-being are the same.
Every proposition of geometry is absolutely necessary, and in this way one talked about an object lying entirely outside the sphere of our understanding as if one understood quite well what one meant by this concept. The unconditioned necessity of judgments, however, is not an absolute necessity of things.
- SapereAude
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Re: Retorsion argument, first principles and non-classical logic
UPD A funny attempt to cope with an apparent Hegel's influence in the history of philosophy. Upshot: Maybe I'm just wrong. Maybe Hegel is king after all. 
Every proposition of geometry is absolutely necessary, and in this way one talked about an object lying entirely outside the sphere of our understanding as if one understood quite well what one meant by this concept. The unconditioned necessity of judgments, however, is not an absolute necessity of things.
- seigneur
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Re: Retorsion argument, first principles and non-classical logic
@SapereAude
Thanks. However, Hegel does nothing to help Ouros. Hegel is as grounded in first principles as anybody else. And so is Advaita Vedanta and Buddhist philosophies that similarly revolve around the idea that everything (and every thing) is a reflection in the mind (the mind being, correctly in my opinion, described as analogous to a mirror in the East).
The shared feature of all these systems is that they are mostly intertwined epistemology and metaphysics. This affects their rhetoric. When it comes to pure metaphysics (ontology in particular), they get quite clear, e.g. in Advaita Vedanta that thou shalt not mix up self and not-self, in Buddhism that it's a fatal error to attribute essence to anything (or any thing), etc.
So, the thing to note is that Hegel is combined epistemology and metaphysics. His main work is titled Phenomenology of Spirit, this should give a clue. It's always important to note what is being talked about. It affects the way it is being talked about and the choice of vocabulary.