...but it seems that Count Timothy von Icarus disagrees. — MoK
Logic as the work of the Devil? The retreat from rationality is the only response left for those who must accept the dogma of the Trinity despite it's incoherence.Wholly instrumental analytic reason is in a sense diabolical (in both its original and current sense). — Count Timothy von Icarus
Many ways. All of them are ad hoc workarounds. Compare the tortured "Socrates is-a-thing-taller-than-Plato" to Taller(Socrates, Plato).It has many ways of dealing with many placed predicates and relations. The ancients and medievals did not lack a notion of polyadic properties. — Count Timothy von Icarus
Aristotle’s logic dominated scholastic philosophy through the middle ages; indeed, as late as the eighteenth century, Kant maintained that Aristotle’s logic was perfect and in no need of revision. But the theory of the syllogism is far too limited to model anything but the most superficial aspects of mathematical reasoning. — Open Logic
What's "Is-ness"? Isn't that a reaffirmation of A=A, that the essence of A is that A is A? Doesn't that leave you with defining the "is" of identity in terms of essence, and then defining essence in terms of identity?the essence is the 'is-ness' of something. — Wayfarer
Davidson is happy to say that people have beliefs, and to use beliefs to explain actions, and says that such explanations are causal.But that snippet gives a hint as to why you can't get opacity with behaviorism. You'll end up with a de re reading of everything. — frank
The standard modern definition of an essence is as those properties had by some individual in every possible world that includes that individual.I don't understand what that definition is referring to unless essence refers to properties and abilities! — MoK
Not sure what that sentence is. The ball remains in your court, so far as I can see.You haven’t given any new effort to show me some pretenses. — Fire Ologist
Unfortunately not.End of discussion. — Fire Ologist
If you really think the God who is a trinity of persons is like the person who is suffering from DID... — Fire Ologist
4. When one is offended by another person, whose fault is that feeling of offense? The hurling of insults is certainly the fault of the one hurling insults, but the feeling of offense, who is responsible for that? — Fire Ologist
Take it up with DSM-5. Are they also full of shit?How is something like “disassocistive identity disorder” even possible to imagine as a coherent thing? — Fire Ologist
And I'll note that you've failed to answer the simple question, — Leontiskos
A part of analytic method is to use formal logic to model natural language. The bits and pieces of a formal logic are much more rigorous than those of a natural language. We can borrow this rigour in order to show clearly some differences in use in natural languages.
This is brought out nicely in predicate logic. Three differing uses of "is" are:
1. The "is" of predication - "The ball is red" - f(a)
2. the "is of equivalence - "Two plus two is four" - a=b
3. The "is" of quantification - "There is a ball" - ∃(x)f(x)
We can see similar uses in a natural language such as English. A clear English sentence containing "is" might be parsed as one of these, but it may be that there are English sentences that include "is" but do not parse into one of these three; or at least that are somewhat ambiguous or difficult. Consider auxiliary uses, "What I’m telling you is, don’t touch that switch." So the list is not intended to be exhaustive.
It's also worth noting that (2) is a special case of (1). The "=" is a binary predicate over a and b.
In syllogistic logic, all relations are reduced to single-places predications. “Socrates is taller than Plato” have to be paraphrased into one-place predicates like “Socrates is-a-thing-taller-than-Plato” before entering a syllogism. Something like "Tully is Cicero" has to be treated not as a relation, but as a single-placed predicate. It has to be treated the same way as, say, "Tully is a writer". Tully is a member of the group of writers, and Tully is a member of the group of things which are Cicero.
An adherence to merely syllogistic logic might explain some of the difficulties had hereabouts.
"=" is reflexive, symmetrical and transitive; A=A; if A=B then B=A, and if A=B and B=C then A=C. Other relations can have all three - if your birth month is your birth month, and if it is the same as mine, then mine is the same as yours, and if mine is the same as yours and yours is the same as hers, then mine is the same as hers. Taken together these three give us equivalence but not identity.
Classically we can add x=y⇔∀P (P(x)↔P(y)), Leibniz’s Law. This is the standard definition of "=" for first-order logics. Two things are identical if they have exactly the same properties.
It's extensional. What that means is that if A=B, then for any theorem that contains "A", we can instead stick "B", without changing the truth value. The truth of the theorem is not dependent on the term used, but on the thing - the extension - of that term. So since "A" and "B" refer to the very same thing, we can swap 'em, and what we say stays true.
But Leibniz’s Law falls over in modal contexts. The Opera House is in Sydney, but might have been instead built in Melbourne (God forbid! Picture it on the banks of that dank cloaca, the Yarra, in the rain...). But if we keep Leibniz’s Law then it would not be the Opera House, that very building, that was built in Melbourne, and so on... The answer to this, From Kripke, is to drop Leibniz’s Law but keep extensional substitution - that is, to use rigid designation. — Banno
I'd say the fact that we don't really know what we are saying with (1) is significant. — Leontiskos
Sure. I enjoyed the OP. As a bit of history it's not problematic...the thrust of this particular OP is historical — Wayfarer
Yes, and arguably neither is Superman in 'Lois is ready enough to say "Superman can fly"', that that sentence is not about Superman, but about something Lous says. I gather your behaviourist is not inferring any intentionality to Lous or to the parrot. Do you know of any one who proposes such an approach?The rigid designator, Superman, isn't in sentence b. All that's there is a sound the parrot is ready to make. — frank
tob. Lois is ready enough to say "Superman can fly."
A supposed substitution?c. Therefore, Lois is ready enough to say "Clark Kent can fly."