news:fdc0b035-535a-476d...@s5g2000vbc.googlegroups.com...
> The distinction between mathematics and logics here is arbitrary.
Arbitrary? I just do not think your proposed definitions capture the
underlying notions: with all due respect, I actually think you have the
thingy upside down...
> Yes my definition fits the *informal* concept of logic, I agree.
That is not what I said: on the contrary, to me your definitions only
capture the formal side of things, and not even that precisely.
> Mathematics is basically a kind of logic.
I would strongly disagree: logic is logic, mathematics is mathematics, and
then maybe mathematics uses logic: for the reasons I am mentioning.
> However here I reserved the
> term "logic" to the arena of Tautologies and mathematics to what
> extends it.
In particular, only in an *already* formal setting you could say the a
logical theory is a collection of tautologies. In fact, logic per se is
founded on the notion of *self-contradiction*, which does have a salient
informal ground, and tautology is defined after self-contradiction. A great
book on the foundations of logic is P. F. Strawson, Introduction To Logical
Theory (there are even few final chapters devoted to inductive inference and
the nonsense of searching for a justification to induction).
<snip>
> anyhow
> I call what can be formalized in those later systems as
> "mathematical".
I understand this distinction between logical and non-logical axioms, but
the "mathematical" system that results from there is, to me, indeed already
and fully mathematical, as we are not anymore interested in pure formal
questions of validity, we are rather interested in proving stuff (within a
consistent system, of course, which is the reason for taking from logic)
about objects and operations, i.e. *factual truths*. In short: logic is
interested in logical truths, mathematics is interested in factual truths
(about mathematical objects).
> Mathematics in the sense I'm speaking of can have parts of it that do
> have grounding in reality, since logic itself actually have some
> overlap with reality.
Logic (the study of *self-contradiction*, usually just called "validity") is
grounded on natural language: you won't be able to discern the logical form
and validity of a statement (i.e. do a logical analysis) unless you know the
meaning of words and connectives. And language is not "reality", hence the
relevant informal notion is that of *mutual incompatibility of predicates*,
not any reference to a reality external to language (to which language has
no necessary reference to begin with). On the other hand, mathematics is
the study of a reality of its own, that of numbers (mathematical structures
in general), an abstract reality, yet a "reality".
> However mathematics may on the other side speak
> about matters that are not observable at all and non virtual in your
> sense, you can call it fantasy mathematics, the point is that it is
> still mathematics.
I rather called it abstract or virtual and I didn't mean anything but the
very opposite of any "fantasy". I used the term "virtual" for applied
mathematics, to mean that in that case we are not anymore dealing with
purely abstract objects, we are rather trying to *model* an external reality
this time (and "virtual" also is supposed to capture the fact that we will
never model reality *per se*, only an abstraction/approximation of it).
> The basic difference between applied mathematics and pure ones is that
> the applied one is an overlap between mathematics and some other field
> of human interest, while pure mathematics is not directly so.
Too weak: it amounts to giving up in providing any pertinent definition.
Yes, our daily practice is never in itself pure (we always do more things at
once, where the single things we do are in fact cut out from the "continual
flow" by our conceptualizations, nothing else). So one thing is that nobody
can do, say, maths without doing maybe a bit of logic, or maybe a bit of
social economy, depending on the specific case, etc. etc. But other thing
is that still logic is logic and mathematics is mathematics, or we don't
know what we are talking about.
> Pure
> mathematics is like Stem mathematics, Primordial mathematics,
> something more general than applied mathematics
It is not simply "more general", it is rather *purely abstract*. In any
case, the difference I am attempting between pure and applied mathematics is
more of a characterization of the two extremes of a range.
-LV