Re: Truth, possibilities, life and computation

Bruce Edmonds (B.Edmonds@MMU.AC.UK)
Tue, 19 Sep 1995 10:22:34 GMT


Don Mikulecky, MCV/VCU/Mikulecky@gems.vcu.edu replies to me:

> You seem to dislike dichotomous categories and (possiblly
> mislabeling them) speak of them as absolutes.

"Absoutist" - a term of my own (inadequate) making, to convey a
point. Dichotomous categories are usually fine at the gross level,
but can be misleading when talking about the edges of their natural
scope. Then they can lead to falacious arguments.

Trivial Example: "Either the chair is in the room or it is not" is
fine in normal usage and valid there, but assuming that for a
particular chair, room and time there is one universal answer to the
question "Is the chair in the room?" is wrong (compare the answers
in these two contexts when the chair is in the doorway to the room:
"If there is a chair in the room, sit on it." - (its not) and "We
suspect the victim was bludgeoned to death with a chair, was there a
chair in the room?" - (there was). More tortuous and logically
ambiguous examples are possible.

A more serious example: "Either something is alive or it is not" is
fine when comparing rocks to cats, but much more doubtful when
considering the emergence of life. Here one has to be careful about
the context and frame of ones usage, if one is not to fool oneself.

> You also seem to think Jeff is speaking about natural systems while
> we tire at reminding you that we are dealing with the mode ling
> relation's right hand side....formal systems. Now do you still
> think the statements apply?

Sometimes, one is justified about being "absolutist" about formal
systems, but not always (as Chaitin shows - he exhibits a finite
integral polynomial, the finiteness of whose integral solutions is
essentially non-formal). So yes, they also apply to formal systems.

> I detect a frustration with two valued logic which i share, but do
> not have the apparatus to circumvent. In the formal approach to what
> we are trying to do, the use of sets, mappings, etc. lead to
> classifications using equivalence classes, etc. Is this absolute?

1. There have been alternatives to two-valued logic for a long time,
Brouwer's intuitionistic approach is around 70 years old, most
mathematics etc. can be done with it. More recently there has been
an avalance of such formal systems. After all non-formal logic was
never two-valued!

2. Sets, mappings etc are usually formulated in classical two-valued
logic (although there are alternatives), but this is fine! The
difficulty (as you well know) is when you use it to model something
else (i.e. its interpretation), including other formal systems! I.e.
there is nothing wrong with two-valued logic (JAFS - Just Another
Formal System, along with hypersets, category theory, ZF set theory,
many-valued logic etc...), its how carefully you apply it!

> I need some clarification. It seemed we were getting somewher,
> but now I feel confused. Life in software? You then reject the
> usual causalities associated with the word and the rest of what we
> have been laboring to clarify?

I am assuming you are refering to my statement that no thing is
*completely* closed to efficient causation. From a pragmatist
perspective that "living things are closed to efficient causation"
is a useful statemtent - it tells us something important. Its
utility is reduced when we are considering the point at which life
emerged (assuming it is a single point!) - this is an exceptional
cirxcumstance at which our rough statement "living things are closed
to efficient causation" is taken to the limit of its utility.
Then we have to go back to our goals and use of such a linguistic
model - one of the terms "living", "closed", "causation", "efficient
(causation)" and "are (is)" are going to have its meaning streached
beyond its original core meaning - we have to choose! Our choice
effect the form of our linguistic model at this point!

I doubt I have made anything clearer! (after all I *am* pointing out
some limits to linguistic clarity).

----------------------------------------------------------
Bruce Edmonds
Centre for Policy Modelling,
Manchester Metropolitan University, Aytoun Building,
Aytoun Street, Manchester, M1 3GH. UK.
Tel: +44 161 247 6479 Fax: +44 161 247 6802
http://bruce.edmonds.name/bme_home.html