Re: Orthography supporting sound changes?

On 12 Jan 2006 04:40:54 -0800, Seán O'Leathlóbhair
<jwlawler@xxxxxxxxx> wrote in
<news:1137069654.532020.152110@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>
in sci.lang:

> Brian M. Scott wrote:

>> On 12 Jan 2006 02:25:27 -0800, Seán O'Leathlóbhair
>> <jwlawler@xxxxxxxxx> wrote in
>> <news:1137061526.982634.167620@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>
>> in sci.lang:

[...]

>>> Also, it is hard to draw a clear line between maths and
>>> physics.

>> Actually, it isn't. The separation is very clear, despite
>> the fact that much mathematics was inspired by physical
>> questions and, conversely, much mathematics is used in
>> physics. The existence of non-Euclidean geometries, for
>> instance, is a purely mathematical result; that some of them
>> are useful in describing the spacetime in which we exist is
>> a matter for physicists.

> Non-Euclidean geometries have as much chance of being
> "real" as Euclidean ones. They are both, at times,
> useful models of real things. How real either is, is a
> difficult philosophical question.

But I'm not talking about 'real'. They exist in the usual
mathematical sense, independent of any possible application
as models of reality.

[...]


>>> Physics is surely the archetypal science. How about
>>> statements such as "You cannot travel faster than light"?

>>> OK, a physicist's "cannot happen" is a bit weaker than a
>>> mathematician's but it is still a strong statement.

>> It isn't the same kind of statement at all. The
>> mathematician's 'cannot happen' refers to a logical
>> impossibility within a well-defined abstract system. The
>> physicist's 'cannot happen' by no means has the force of a
>> logical impossibility.

> The physicist's statement is nonetheless a strong
> statement and if a physicist said: "X cannot happen . .
> .", I would expect him to be prepared to justify his
> assertion. That is what I see as common between the
> mathematician's "cannot happen" and the physicist's
> "cannot happen".

Strength is not the point. The point is that the two have
completely different logical status. And the expectation
that the speaker be prepared to justify the claim seems to
me wholly irrelevant.

> Of course, the justification is likely to take a different
> form but the justification of "cannot exceed the speed of
> light" is more mathematical than experimental.

'In a universe in which conditions C_1, ..., C_n are true,
one cannot exceed the speed of light' can probably be cast
as a mathematical result; 'one cannot exceed the speed of
light' is in no sense a mathematical result.

Brian
.

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