Moderators: theropod, Blip, Spinozasgalt, Durro
Cito di Pense wrote:
Self-evident is not the same as necessary. Necessity is the result of deduction, and hence is not a priori.
Postulates are not the same as axioms. A postulate might be something you have decided to try to prove, otherwise, axioms and postulates would be the same. Why have two words if there is only one concept. Parsimony demands it.

Sweenith wrote:Cito di Pense wrote:
Self-evident is not the same as necessary. Necessity is the result of deduction, and hence is not a priori.
Postulates are not the same as axioms. A postulate might be something you have decided to try to prove, otherwise, axioms and postulates would be the same. Why have two words if there is only one concept. Parsimony demands it.
Agreed, something can be necessary without being self-evident (also, something can be self-evident without being necessary).
And while it's true that the conclusion of a valid deductive argument follows necessarily from the premises (meaning if the premises are true, then the conclusion can't fail to be true), that doesn't mean that the conclusion as such is a necessary truth (the conclusion, along with its premises, could be contingently true). Moreover, a proposition is either necessarily or contingently true regardless of whether we arrive at that proposition via deduction (ex: it would still have been true that 2 and 2 makes 4 even if we had never deduced it).
In any case, a priori knowledge doesn't mean "not the result of deduction," it just means that it doesn't depend on empirical or experiential evidence. So even if it were granted that necessity is always only the result of deduction, it still wouldn't follow that necessity cannot be a priori.

Cito di Pense wrote:Sweenith wrote:Cito di Pense wrote:
Self-evident is not the same as necessary. Necessity is the result of deduction, and hence is not a priori.
Postulates are not the same as axioms. A postulate might be something you have decided to try to prove, otherwise, axioms and postulates would be the same. Why have two words if there is only one concept. Parsimony demands it.
Agreed, something can be necessary without being self-evident (also, something can be self-evident without being necessary).
And while it's true that the conclusion of a valid deductive argument follows necessarily from the premises (meaning if the premises are true, then the conclusion can't fail to be true), that doesn't mean that the conclusion as such is a necessary truth (the conclusion, along with its premises, could be contingently true). Moreover, a proposition is either necessarily or contingently true regardless of whether we arrive at that proposition via deduction (ex: it would still have been true that 2 and 2 makes 4 even if we had never deduced it).
In any case, a priori knowledge doesn't mean "not the result of deduction," it just means that it doesn't depend on empirical or experiential evidence. So even if it were granted that necessity is always only the result of deduction, it still wouldn't follow that necessity cannot be a priori.
You're bullshitting me. Or else you are putting way more into 'necessary' than it can carry. It's just a word in the English language.
Some statement that is not self-evident, and not deduced, and not evident by empiricism? We need examples. Inquiring minds want to know.
I could grant that there is a priori knowledge, but that it is contingent on not being shown the door, not being handed your hat. That door-showing and hat-handing is the province of science. You could presently claim as a priori knowledge that there are other intelligent species in the universe besides human. Pending a definition of 'intelligent'. Or you could claim that there are no intelligent species, including the human. Pending blah blah blah.

Sweenith wrote:
All I mean by "necessary" is this: a proposition or statement is necessary if and only if it's impossible for it to be false (like "2+2=4" or "All squares have four sides"). On the other hand, there are certain facts that could have been otherwise than they are, such as the fact that I live in Chicago, or the fact that my computer monitor is to the left of my can of diet Dr. Pepper—the universe might have been organized in such a way that I ended up in Japan, say, or that my monitor was to the right of the can instead of the left—these facts are not necessary, because it was possible for them not to be the case.
Sweenith wrote:
First off, what I said was that a priori knowledge doesn't have to be knowledge that's not the result of deduction - i.e., a priori knowledge may or may not be deduced. Secondly, what I said was that a priori knowledge doesn't depend on empirical evidence, not that it couldn't be learned empirically (it may or may not). So I never said anything about a statement that's not deduced and not evidenced empirically.
I don't see how "there are other intelligent species in the universe other than humans" or "there are no intelligent species in the universe" could be known a priori, because the truth of either one depends upon the sorts of physical entities which exist in the universe, and facts like that can only be known from observation. Additionally, that fact—(that there are intelligent beings in the universe)—is contingent, and could have been different; as such, it's not necessarily true, and thus (absent of being a "synthetic a priori" truth), can't be known a priori.

Cito di Pense wrote:Sweenith wrote:
All I mean by "necessary" is this: a proposition or statement is necessary if and only if it's impossible for it to be false (like "2+2=4" or "All squares have four sides"). On the other hand, there are certain facts that could have been otherwise than they are, such as the fact that I live in Chicago, or the fact that my computer monitor is to the left of my can of diet Dr. Pepper—the universe might have been organized in such a way that I ended up in Japan, say, or that my monitor was to the right of the can instead of the left—these facts are not necessary, because it was possible for them not to be the case.
You're now behaving as if this conversation has never taken place before, let alone hundreds of times in this forum alone. What is your point? To observe that people have tried to define the words 'necessary' and 'contingent' as exercises in logic? Do you propose to instruct me in standard definitions of necessary and contingent as presented in your logic classroom? Then you are making your use of the word 'necessary' contingent on some definitions established in the logic classroom. That's OK with me, too, but this is just an internet forum, a chance for you to try to comminicate clearly what your intentions are. If you have any.
You have not made a coherent effort at creating anything but a tautology. Perhaps you mean that a priori knowledge is dogmatic. You still have not shown me how the term should be used 'correctly'. Either make a statement of a priori knowledge, like 'God exists' or some act of mental telepathy, or go home. You haven't even started in with knowledge, let alone gotten to a priori knowledge. You're just using the term because somebody else used it.
Essentially you are saying that self-evident axioms are necessary truths, but you haven't given any examples of such axioms. I would say that self-evident axioms are self-evident, to show you what I mean by 'tautology'.
"All squares have four sides" is part of the definition of 'squares'. Don't be square, daddy-o, be hip to the jive. It's not 'necessary' that squares have four sides. We could have called them 'frambelisks'. It's not necessary that they have four sides, because you have to define the number '4' first. Perhaps you think that the natural numbers are 'necessary'. You should have said that to start. At least you'd be able to quote somebody famous:
"God created the integers," wrote mathematician Leopold Kronecker, "All the rest is the work of Man." Maybe you wish to say something similar about modus ponens. Modus tollens? If you're not metabolising, and created by god, you're not alive.
Saying that there are intelligent species in the universe depends on calling whatever we are doing here 'the exercise of reason'. The debate about what part of mathematics is synthetic is actually an ongoing debate among philosophers. I don't know the technical term for this. Instead, I learned how to use mathematics, a very little bit. What we are doing here is the exercise of language. I call that, in context, 'wibbling'.
What I mean is that, if I wanted to learn a conventional set of definitions of necessary, contingent, and a priori, I would go to a university and pay tuition so I could have something on a transcript certifying that I knew something. Been there. Done that.

Sweenith wrote:
examples of a priori knowledge: "2+2=4" "no bachelors are married" "all squares have four sides of equal length" those are knowable a priori, because they can be grasped via reason alone.
Therefore, just because something is self-evident doesn't mean that it's necessarily true.
No I think God has created every existing thing about from himself, but I don't think he created the rules of logic (that seems to be an incoherent idea).
So much for Aristotle's "ALL men by nature desire to know" (first line of the Metaphysics)
Sweenith wrote:I'd love to go without having to define the same old terms over and over, but then people just talk past one another.

Cito di Pense wrote:Sweenith wrote:
examples of a priori knowledge: "2+2=4" "no bachelors are married" "all squares have four sides of equal length" those are knowable a priori, because they can be grasped via reason alone.
Incredible. What is prior to making those statements is knowing (or agreeing to) the defintions of 'addition', 'equality', 'bachelor', 'married', 'square', 'side' and 'length'. Having a definition of a geometric square is contingent on having seen or made an approximation of it on the ground. You can go with Kant, and say that space and time are prior to reason, but that's an observation, since humans evolved from bacteria.
Yes, you're coming at this from a philosophical POV, and like the notion that philosophers work things out from first principles. My view is that all those first principles come by way of the empirical. The best you can do is to suggest that it is reason that imposes order on the empirical, but that is an axiom, and not an a priori. Is the order there first? Can you say that evolution (of reasoning) is possible without some sort of prior order? Is that an observation or a deduction? If the latter, it is perhaps the self-evident axiom you are looking for, and it is not the foundation for philosophy, but for science.
I see no guarantee that the exercise of pure reason gives you anything but that, and you have to stop there, because you can't make your definitions do anything much by invention of definitions. If modus ponens works consistently, it is because there is consistency. It's not saying much.
Cito di Pense wrote:Well, that's bad for you, since the existing order in the universe will break down, according to the laws of entropy and high energy physics.
Meh. There is not anything necessarily true, since no truth is not a statement. That's only a definition.
Cito di Pense wrote:No I think God has created every existing thing about from himself, but I don't think he created the rules of logic (that seems to be an incoherent idea).
That's nice, Sweenith, but it is a nonsense statement about a nonsense entity. Kronecker's statement is ironic. Even if Kronecker actually believed in God, he only could use it as an axiom, and ironically so. IOW, if you want to talk about authentic a priori knowledge, you will need to talk about God, but that is nonsense. All you will have is connection between necessary truth and the word 'God'. Done with you.
Yep. God has ordained it. If you find yourself having to talk about what is prior to everything else, you're doing theology, and not philosophy. Go to the Theism forum, or find somebody else to do it with, here. Theology does not involve the exercise of reason, but the construction of a lot of very trivial tautologies. Not interesting to me.
Sweenith wrote:I'd love to go without having to define the same old terms over and over, but then people just talk past one another.
Well, you won't find me trying to talk past you. I'm very plain spoken, am I not? Why did it take us so long to bring God into this? To say that such conversations are about God? You and I can have a conversation about something I will say is nonsense. Speculating about necessary truths is a preamble to discoursing about God. It's just that once we start talking about God, it is plain that we are talking about bullshit. Are we not plain-spoken?



You can treat other approaches as 'discourses' (methodologically speaking). Discourse is like a 'talking cure'. Sometimes it works, but you don't really know how it works. I think it works by getting you to think about something other than what was bothering you.
I read Sweenith like a book, when he starts talking about 'innate knowledge'. He's after the sensus divinatus.



Users viewing this topic: No registered users and 1 guest