On 7/22/2011 2:08 AM, Bruno Marchal wrote:
On 21 Jul 2011, at 17:54, meekerdb wrote:
On 7/21/2011 2:27 AM, Bruno Marchal wrote:
But I think you beg the question by demanding an axiomatic
definition and rejecting ostensive ones.
Why?
The point is that ostensive definition does not work for justifying
an ontology.
That seems to be a non-sequitur. How can any kind of definition
justify an ontology?
Because a definition or an axiomatization refer to an intended model,
of a theory which handle existential quantifier. The theory of group
requires the existence of a neutral elements, for example. The theory
of number requires zero, etc.
Satisfying an existentially quantified proposition implies existence
within that model. It doesn't justify the model or its ontology.
Definitions are about the meaning of words. If I point to a table
and say "Table." I'm defining "table", not justifying an ontology.
OK. And then what? You are just pointing on some pattern.
That's what the dream argument shows. Being axiomatic does not beg
the question. You can be materialist and develop an axiomatic of
primitive matter. The whole point of an axiomatic approach consists
in being as neutral as possible on ontological commitment.
But what you demanded was a *physical* axiomatic definition. Which
seems to be a demand that the definition be physical, yet not
ostensive. I think that's contradictory.
I did not asked for a physical axiomatic definition, but for an
axiomatic definition of physical (and this without using something
equivalent to the numbers, to stay on topic).
An axiomatic definition isn't possible except within an axiomatic
system. The whole argument is over the question of whether the physical
world is an axiomatic system. I think it very doubtful. The model of
physics takes "x exists" to mean we can interact with x through our
senses (including indirectly through instruments which exist), but this
is not an axiom.
Axiomatics are already in Platonia so of course that forces
computation to be there.
The computations are concrete relations.
If the are concrete then we should be able to point to them.
Either by concrete you mean "physical", and that beg the question.
It was your word.
If not, I can point on many computations is arithmetic.
No, you can only point to physically realized representations.
This needs Gödel's ariothmetization, and so is a bit tedious, but it
is non-controversial that such things exist. Indeed RA and PA proves
their existence.
They don't need axioms to exist. Then the numbers relation can be
described by some axiomatic.
And one can regard the numbers as defined by their relations. So the
"fundamental ontology" of numbers is reduced to a description of
relations. The is no need to suppose they exist in the sense of
tables and chairs.
Indeed.
This means only that we *can* agree on simple (but very fertile)
basic number relations. For primitive matter, that does not exist,
and that is why people recourse to ostensive "definition". They
knock the table, and say "you will not tell me that this table does
not exist". The problem, for them, is that I can dream of people
knocking tables. So for the basic fundamental ontology, you just
cannot use the ostensive move (or you have to abandon the dream
argument, classical theory of knowledge, or comp). But this moves
seems an ad hoc non-comp move, if not a rather naive attitude.
What "dream argument"? That all we think of as real could be a
dream? I think that is as worthless as solipism.
This is the recurring confusion between subjective idealism and
objective idealism. Objective idealism is not a choice, but a
consequence of the comp assumption and the weak Occam razor.
And the assumption that the UD exists (?)
Brent
Bruno
http://iridia.ulb.ac.be/~marchal/
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