Time

[Howard Pattee <***>]

Judith,

Time is an eternal mystery and therefore a good topic for discussion.
Your father and I often speculated about it, often over after-dinner
brandy. One's concept of time affects one's world view and consequently
how we think of time influences our models of the world. Mathematicians
and physicists usually differ on the significance of time, and I think
this is really the only basic difference in Rosen's and my approaches to
biology. I want to stress that these are complementary views. We
understood and accepted each others views very well. Both are necessary
even though they may appear paradoxical.

To back up, you asked why I referred to time as one dimensional. I
answered it was because time can be represented in a model by a scalar
number. You replied, "that's not a very accurate representation of
what I perceive about reality." Of course, that is true for all of
us. "Numbers on a line" is not the way we perceive time, but
that is one way we represent time in physical models. 

If you read pages 50 et seq. of AS, Rosen makes this distinction in
detail. Perceived time and measured time are quite different. [Chapter 4
is all about continuous and discrete encodings of time, but it is
technical.] Both processes are much more complex than our instincts lead
us to believe. He also explains that a clock neither perceives time or
measures time, but only  generates labels for other observables that
we measure.

It is only reasonable that the mind of the working mathematician is not
concerned with time or rates since nothing he does with his images or
symbols depends on time or rate. Experimental physics is all about rate
equations, so time is on physicist's minds. Except one apparent paradox
is that physics is looking ultimately for relations between temporal
events that are timeless. That is, the laws of Nature do not change in
time. For example, the Conservation of Energy would not be a law if this
were not the case. In this sense the laws of physics form an entirely
timeless relational science. 

Put in my own words, as briefly as possible, Rosen wanted to create
relational models of living systems that were timeless as are physical
laws. To do this it would be necessary to generalize the laws of physics
to include life, leaving physical laws as special cases. As Rosen
recognized, living systems are open and evolving systems so they can have
no material or energy conservation laws. This means that the conventional
simple physical observables of organisms cannot be put into timeless
relations. Therefore, to achieve a relational biology Rosen abstracted
away time (as represented in physics by the rate-dependent dynamics of
temporal state transitions) and focused his models on the
rate-independent functional or informational entailments that
characterize life.

Left over comments:
Judith: Why do you say that there is no way to measure the importance of
semantic information? 

HP: I meant there is no good universal measure. As you say below, every
organism has its own measures of importance.

Judith: That's semantic information specific to each species, and it gets
even more specific with various varieties within species-- and we've
figured a lot of that out, too. In a sense, the semantics are what are
encoded into the "internal predictive models" my father spoke
of in Anticipatory System Theory.

HP: Exactly so.

Howard