logical constants fix the truth value of logical expressions.

vectorcube

Fri 10 Jul, 2009 01:55 am
@kennethamy,
kennethamy;76268 wrote:
That there is no mention of truth does not mean that truth isn't there anyway. What does it mean to say that the conclusion is derived from the premises?

Why not? I can derived the statement 1110111 given the initial condition of 0, and the rule x-> 1x1. One can get 1110111 by apply the rule to 0 three times. The is nothing wrong with seeing formal structure of logic as rules and operations.

kennethamy

Fri 10 Jul, 2009 06:40 am
@vectorcube,
vectorcube;76278 wrote:
Why not? I can derived the statement 1110111 given the initial condition of 0, and the rule x-> 1x1. One can get 1110111 by apply the rule to 0 three times. The is nothing wrong with seeing formal structure of logic as rules and operations.

The question was what does it mean to derive this from that. Not to give me further examples of derivation. Please answer the question. Don't give me another example of derivation.

vectorcube

Fri 10 Jul, 2009 08:33 am
@kennethamy,
kennethamy;76288 wrote:
The question was what does it mean to derive this from that. Not to give me further examples of derivation. Please answer the question. Don't give me another example of derivation.

I think your question is crazy. It is like asking people what it means to walk. I bet you already know how to walk, so why do you need to know what it means to walk? "Derivation" is a primitive. To ask such a basic notion is like asking what is the deal with walking. You know how to do it. You don` t need to know why.

The meaning of a proposition is just it` s truth value. I think Davidson said it. That is, meaning is about semantics, or, the question of "what is true?"

kennethamy

Fri 10 Jul, 2009 08:46 am
@vectorcube,
vectorcube;76317 wrote:
I think your question is crazy. It is like asking people what it means to walk. I bet you already know how to walk, so why do you need to know what it means to walk? "Derivation" is a primitive. To ask such a basic notion is like asking what is the deal with walking. You know how to do it. You don` t need to know why.

Whether or not I know what it means to walk is one question. Whether I need to know what it means to walk is a different question. You are fairly good at diversion, but not good at answering. Try answering the question, please without diverting it to something else. "Derivation" is not a primitive, since I can define it.

Next.

vectorcube

Fri 10 Jul, 2009 09:02 am
@kennethamy,
kennethamy;76324 wrote:
Whether or not I know what it means to walk is one question. Whether I need to know what it means to walk is a different question. You are fairly good at diversion, but not good at answering. Try answering the question, please without diverting it to something else. "Derivation" is not a primitive, since I can define it.

Next.

How do you define "derivation"?

The meaning of a proposition is just it` s truth value. That is, to ask about meaning is about semantics, or, the question of "what is true?". Why is this related to derivability, or fornal rules?

You said you want to know(justified true belief). In this case, derivability is not true. Derivability is a normative notion. You just do it, because it is good to do it. Just like it is good to not get piss off so easily.:sarcastic:

next:a-ok: