The S-K modeling math is in
an area that’s been thought “mysterious”:
But we should be able to
ask: “What are the arithmetical rules
that connect measurable circumstances to abstract math?”
Big questions:
Basic answers:
Here’s a question that is
practical, but outside pure mathematics:
Here’s a case where the
answer matters:
The question of which is
right is NOT A QUESTION OF PURE MATHEMATICS.
Analogies between the
measurable world and pure math are wonderfully useful, but the abstract “game”
of mathematics is not the same as the measurable world.
What’s pure math?
Mathematicians define
numbers from axiom systems. Here are the Dedikind-Peano axioms commonly used to
define
the numbers mathematics use:
Pure math is so practically
useful because it can form powerful, flexible analogies to physical things.
Math modeling is reasoning
by analogy. We need good analogies.
People find physical laws by
a process of exploration and refinement on the basis of experience. That’s been going on for thousands of
years, and especially over the last three centuries.
Steve Kline and I decided to
call these constants “natural law operators.”All are defined according to the
same pattern:
Example: A resistance per
unit length determined for a specific wire for ONE specific length increment
and ONE specific current works for an INFINITE SET of other length increments
and currents on that
wire (holding temperature the same.)
Natural law operators work
just like dimensional numbers when they are used in exact correspondence with
the equation that defines them.
But we have practically no
experience with compound natural law operators that contain spatial increments,
and the experience we have has often been treacherous.
Wholes should equal the sums
of which they consist.
To derive a differential
equation from a physical model:
In such a case, two
equations are implicitly defined in terms of each other.
Slide 21
When we go from our physical
representation, set out as a measurable thing, to an abstract mathematical
representation of it, we’re making a jump.
Here we are, facing the question:
Our notation isn’t clear
about when a symbol stands for a physical model in real detail, and when the
notation is a system of “meaningless signs.”
Slide 24
When you continue the
expansion, you get relations that set out PHYSICAL interactions, but are not
yet abstract, in an equation representation like this:
Here’s one of the
crosseffects. It stands for a physical
interaction, and is notated so that the arithmetic within the curly bracket is
left to be determined.
We’re perfecting an
analogy-making procedure, beyond pure mathematics, so that we can represent
things within pure math.
Slide 28
Here’s the new rule that
passes loop tests:
You can look at the case in
a more general way that turns out to rule out terms now called “infinities”
that come from some modeling, as well as infinitesimals.
Are these statements true?
Here, “true” must mean:
I believe, and Steve Kline
believed, that the logical consistency was there ACCORDING TO THE PATTERN
MATCHING STANDARDS RELEVANT TO THE CASE.
Is this new concrete domain
to abstract domain mapping procedure consistent with all the evidence?
Direct tests are
fundamentally important, and I’m hoping to interest some of you in helping with
such tests.
For now, I hope I’ve made
you open-minded about this question: