Introduction
There are two kinds of models, centralized or top-down,
and distributed, or bottom-up models. Most physical models are of the first
kind. They are governed by top-down laws that control entire systems. None
of these suffices to describe even the simplest organism, which is complex
and its properties emerge. Traditional mathematical tools fail to untangle
life's complexity. We may distinguish between two kinds of complexity
linear and non linear. Only the first can be resolved with traditional
mathematical tools like logic, or induction. Life's complexity is non linear.
The Game of Life,
a bottom-up model, is even
more unpredictable than the Mandelbrot set, since it lacks a geometry or
mappings which might summarize (or simplify) its emerging structure .Despite
its name, the Game of Life does not capture the
behavior of the simplest life form.
Neither do Artificial Life (AL) models, like Neural Nets, or Genetic
Algorithms. They generate extremely complex structures whose properties
emerge unpredictably, nevertheless they do not capture a profound attribute of life, which is oriented turnover.
Life is an oriented change. Like a river that flows in one direction. Yet even a river could not
serve as an adequate model for life, since its water is carried to the sea
as such and does not change, while the ingredients of life continually
transform. Fire might be regarded as
best metaphor for life. It is born in the burning wood. As it raises upward, its color continually changes, from yellow
to red, and blue. None of AL
models can simulate a fire, neither a river, and yet some serious scientists
claim that these simplistic models are a form of life, life in silico.
And
here comes Wolfram's book "A
New Kind of Science" (1). Might cellular automata (CA) simulate life
better than other AL models? Chapter 8, "Implications from Everyday
Systems" is an attempt to show that CA are indeed the best tool for simulating life. Yet the examples
are less convincing. Like the
fractal nature of plants and animals (p. 400). Life is more than that, since
it defies any geometry. Or
the implicit adoption of the central dogma of molecular
biology according to which there exist a linear mapping from genotype
to phenotype.
One is impressed with Wolfram's success to simulate a river
(p.376), which cannot be done with other AL tools. Or
the oriented change of a fire.
What about life? CA are infinite and immortal, while life is not. They consists
of simple geometrical structures like triangles, while life is amorphous.
Biological age
In the present study every
CA is endowed with a
biological age. A death mechanism eliminates
the old and spares the young. You plant a single CA, called zygote,
whose age is zero. Select a rule and a death mechanism,
, and start iterating in the same way as described in Wolfram's book.
Cells age and ultimately die, and you confront an
artificial creature which simulates life. You watch it grow and respond
to stimuli and start contemplating some biomedical concepts.
The experiments described
herewith are designed for evaluating concepts which apply to real life.
Like what causes change? Or what is creativity?
Here are some concepts which
were evaluated on CA models:
1. Medicine: Health , disease, immunity,
injury and repair , and infection.
2. Biology: Biological and chronological time, biological
age, and evolution.
3. Molecular Biology: Cloning , and knockout
genes.
4. Philosophy: Creativity ,
Aristotle's four causes , Kant's synthetic a priori
statement , and recollection.
5. Computer: Distributed memory. Massively
parallel non linear computer.
My objective is to design a model which will simulate how the wisdom of our body (WOB) functions, and eventually draft a new kind of computer. The following chapters are my log book. The CA creature and its universe reveal a fantastic world which beats any intuition, and I explore it in the same way as I learned to explore biomedical phenomena. The log book is not a didactic exposition of the CA world, rather it describes interesting experiments which I am doing as I go, and some thoughts which they evoked in me. Go and get the taste of it.
Chapters 1 - 95: Random explorations.
Chapters 96 onwards: A Model of my theory "A
New Kind of Medicine".
The theory is described in another
section.
References
1. Wolfram S. A New Kind of Science
ISBN 1-57955-008-8