constructor paper - little criticism/query

[hibbsa]

"Constructor theory seeks to express all fundamental scientific theories
in terms of a dichotomy between possible and impossible physical
transformations – those that can be caused to happen and those that
cannot. This is a departure from the prevailing conception of
fundamental physics which is to predict what will happen from initial
conditions and laws of motion."

I can see that you are taking things in a distinctive direction, but I'm
not sure your characterizations above tease that distinctiveness out.

The dichotomy of possible vs impossible is deployed throughout science.
The naming/labeling differs but the purpose tends to be about
identifying constraints. "Constraint oriented" methodologies are
powerful....depending on how constrained something is, identifying what
those constraints are go a long way to identifying what the 'something'
is.

It does appear that your method is constraint oriented, in that you seek
to constrain what things can be or do, by identifying what they cannot
be, or do. I genuinelly don't think any of this represents the new
distinctiveness you are bringing. I see that coming at deeper level of
detail.

Same goes for the final sentence, where you say you are departing from
prevailing conceptions (initial conditions, working out what something
will do etc). I think that for this to be so, science would have to be
using such approaches for trying to identify what things are -
something that science does do but but in the even the approaches are
not a million miles from what you are doing.

The prevailing conception as you state it, relates exclusively to
objects that have already been defined as real, and their possible
characteristics already distinguished from the impossibility space of
what they aren't. Predicting what such objects do, using initial
conditions occurs within some further context (time, space, temperature,
etc).

It is true that your theory will remain abstract so you won't find
yourself predicting behaviour in specific physical contexts. But what
you will be doing is seeking to 'firm up' abstract objects, and then
compute consequences. Which is the most direct parallel for what the
physicists are doing when they measure what objects do. Likewise, when
they seek to define and formulate theory, processes of elimination,
'constraint oriented' processes, are very much the order of the day.

So...in summary....while I perceive there is new distinctiveness, I
don't think your characterizations capture what that distinctiveness is.
One downside I suppose will be a degree of inexplicit confusion in
people reading the paper. If they are scientists they'll probably
recognize something isn't right with how you position your theory....but
they won't necessarily be motivated to put the effort into straightening
things out.

I apologize if I've got things horrendously wrong here. I admire the
theory which is why I try to understand the new distinctiveness.



[Non-text portions of this message have been removed]

[David Deutsch]

Post by hibbsa

"Constructor theory seeks to express all fundamental scientific theories
in terms of a dichotomy between possible and impossible physical
transformations - those that can be caused to happen and those that
cannot. This is a departure from the prevailing conception of
fundamental physics which is to predict what will happen from initial
conditions and laws of motion."

I can see that you are taking things in a distinctive direction, but I'm
not sure your characterizations above tease that distinctiveness out.
The dichotomy of possible vs impossible is deployed throughout science.

But not fundamental physics. That has, instead, the dichotomy between what happens and what doesn't.

Post by hibbsa
The naming/labeling differs but the purpose tends to be about
identifying constraints. "Constraint oriented" methodologies are
powerful....depending on how constrained something is, identifying what
those constraints are go a long way to identifying what the 'something'
is.
It does appear that your method is constraint oriented, in that you seek
to constrain what things can be or do, by identifying what they cannot
be, or do.

Constructor theory is not a method or a methodology but a theory about what the laws of physics, objectively, are. Laws that are deeper than currently known laws. The idea of 'constraints', and the possible-impossible dichotomy, and the idea of causation, and various classes of counterfactual statements, are all in common use in everyday life and in the applications of science. These are all, in my present view, examples of informal constructor-theoretic ideas. Yet they appear nowhere in laws of physics, and are notoriously difficult (the consensus has been that they are impossible) to reconcile with them.

-- David Deutsch