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Artificial Life
 ARTIFICIAL LIFE

"Life is an information process" (John von Neumann).

"Life happens on a virtual checkerboard. The squares are called cells" (John Conway).

"We want to create life in the computer and not in test tubes" (Christopher Langton)

"Life is an evolving software" (G. Chaitin).



Artificial Life

Artificial life −abbreviated, AL or ALIFE− is a relatively new field that attempts to simulate biological processes using computer (computational) methods. AL is the study of life in the digital environment.

According to Christopher Langton −the first to use the term "artificial life"− AL is "the field of study devoted to understanding life, attempting to abstract the fundamental dynamic principles underlying biological phenomena, and recreating those dynamics in other physical media such as computers by making them accessible to new kinds of experimental manipulation and testing."

The AL was born out of the need for a theoretical, computational type of biology based on universal laws. Its objectives are:
Cellular automata

AL was born with cellular automata (CAs). An CA is a type of finite automaton consisting of: The fact that simple rules can produce extraordinarily complex behavior makes CAs a possible theoretical foundation for life and, by extension, for intelligence. Indeed, CAs make it possible to simulate the functions of: interaction with the environment, evolution, as well as coexistence and competitiveness of various life forms sharing the same environment.

CAs were devised by Stanislaw Ulam, but it was John von Neumann who pushed them forward as a computational model by using them to implement a theoretical machine capable of self-replication. Von Neumann is considered "the father" of AL.

Von Neumann called self-reproducing machines "Universal Assemblers". One of the concepts he defined was the "universal constructor", a device capable of constructing another identical machine from its own structural and constructive description, a mechanism also possessed by cells, which contain not only information about their structure, but also about how to construct other cells of the same type. At first, von Neumann's self-reproducing machine was considered an impossible task, on the grounds that such a machine should contain a description of itself, and that this description would also need a description, and so on ad infinitum.

In lectures he gave at Princeton in 1948, von Neumann said that a self-reproducing machine would have to have at least 8 different kinds of parts: 4 for the brain and 4 for the motor part. His machine came to have 29 states per cell (states identified according to their functionality) and a single transition rule, but was never finalized due to his untimely death. Since then several attempts have been made, without success, to complete his work.

Von Neumann proved that a machine can create another machine more complicated than itself. There can be generations of machines, each more complex than its predecessors. This is the same thing that happens in biological evolution. Von Neumann showed that even the complexity of living organisms can be reduced or compacted into a relatively simple set of recursive rules. Self-reproduction can be understood as the consequence of a simplified "physics" based on a cellular automaton. According to von Neumann, biological reproduction is mechanistic and a definition of life can be formulated in terms of information.

According to Ed Fredkin: The universe is really a gigantic computer, specifically a gigantic CA. CAs are, in essence, worlds not unlike our own. There is an information process that underlies everything. "If something cannot be done in a computer, then we cannot do it by a purely mechanical process." And the living organisms that inhabit this universe operate on the same principles as computational processes.


The game of life

The "game of life" was invented by John Conway in 1970 when he was trying to drastically simplify the rules and states of von Neumann's self-reproducing machine. It is a two-dimensional cellular automaton that represents the paradigm of dynamic complexity from the simple: three very simple rules applied successively (to an initial configuration of black cells) can produce extremely complex dynamic results. The rules are as follows:
  1. If a black cell has 2 or 3 black neighbors, it remains black (survives).
  2. If a white cell has 3 black neighbors, it becomes black (revives).
  3. In all other cases, the cell remains white (if white) or becomes white (if black).

RuleBeforeAfter
1. A living cell with 2 or 3 living neighbor cells survives.
2. A dead cell with 3 living neighboring cells revives.
3a. A living cell with less than 2 living neighboring cells dies.
3b. A living cell with more than 3 living neighboring cells dies.

Features: The game of life is the best example of cellular automata and the paradigmatic application of computational biological processes. It contributed decisively in spreading the concept of CA, becoming a source of inspiration for researchers. Due to the simplicity of the rules and the enormous number of dynamic forms it can generate, the game aroused great interest and became popular almost instantly, even becoming a cult object during the 1970s and later. It was easy to experiment with using the personal computer, you could see on the screen how an artificial "living being" evolved. It was also the precedent of fractals, as some shapes are reminiscent of these recursive geometric forms.

Here is an example of an oscillating configuration of period 3:


Christopher Langton was captivated by Conway's Game of Life. From the moment he met him, he pursued the idea that it was possible to simulate living creatures on the computer. After years of study, he tried to simplify von Neumann's CA from 29 states to just 8. In 1979 he achieved the first self-reproducing computational organism using a personal computer.


Wolfram's vision

Wolfram showed in his book "A New Kind of Science" that CAs allow many complex shapes to be generated from very simple deterministic rules applied recursively. That CAs make it possible to create a new kind of science for modeling physical phenomena, a simpler, more direct and visual alternative to cryptic differential equations. Wolfram explored and categorized the types of complexity that CAs produce and showed how they could model the forms of nature such as seashells and plant growth. Wolfram saw the computer as an ideal abstract territory for experimentation, and CAs as the simplest and most powerful system.


The bioforms of Richard Dawkins

Bioforms (biomorphs) are digital creatures produced by computer by Richard Dawkins, who describes them in chapter 3 of his 1986 book "The Blind Watchmaker" [1993], a text popularizing neo-Darwinism, of which he is an advocate. Dawkins wrote the program (which he called "Evolution") to illustrate how complex meaningful bioforms can be created without a designer. Bioforms constitute a bridge between neo-Darwinism and AL.

A bioform is a 2D, tree-like graph, generated by a recursive algorithm, that reproduces and mutates like a living thing. Initially, the graph is very simple, but after a number of steps (recursions) it can become a very complex graph. The initial parent bioform is a vertical line segment. From this segment other segments branch off, and from these other segments, and so on until all the intended recursions are completed.

A bioform has 9 genes (numbered from 1 to 9). Each gene represents an aspect or parameter of the bioform. It can take an integer value between −9 and +9. Dawkins did not elaborate on the parameters, but gave some clues such as the number of branches, length of each branch and the branching angle. The last gene (the 9°) is the depth of recursion. The genes in the bioform reflect the external appearance (the phenotype) and its evolution, analogous to what happens with biological genes. Since there are 9 genes and 19 possible values for each gene, the number of different possible bioforms is 1919. In Appendix I of his book, Dawkins presented an extension of the algorithm with 16 genes instead of 9.

The evolutionary process of a bioform is as follows: By selecting in each generation the form that is closest to what is desired, anything can be achieved.

When Dawkins ran his bioform evolutionary program, he was amazed at the great variety of forms that appeared, reminiscent of real-world biological forms such as insects, trees, flowers, shrubs, beetles, butterflies, spiders, frogs, scorpions, bats, etc.. But non-biological forms also appeared, such as Aztec temples, Gothic church windows, scales, goblets, and even letters of the alphabet. Then Dawkins became aware that he had created a universe of forms which he called "Biomorph Land".

Dawkins saw that, in order to construct a practical biological universe, he had to restrict the possible forms to only those that made interesting biological sense. One of the restrictions he used, for aesthetic reasons (and also to economize on the number of genes needed), was to establish a left-right symmetry, the same criterion used in the Rorschach test of inkblots.

Holy Grail and Christmas Tree.

Devil and The Queen of Spiders

In one of his forays into this universe, he happened to come upon a chalice-shaped pattern that captivated him greatly and which he named "Holy Grail" (see figure), but he failed to retrieve the sequence of changes for his generation. He offered a $1000 prize to the person who could generate it. Thomas Reed (a software engineer from California) found it and won the prize. A few weeks later two other searchers, independently, also found it.

With his bioform generation program, Dawkins intended to demonstrate: Dawkins' bioforms and his conclusions have received several criticisms. The main one is on the grounds that a selection mechanism that requires a human agent cannot be Darwinian. To this Dawkins replies that the selection used is not natural but artificial. To this it is objected that the selection should not be qualified as artificial but as human.


Characteristics of AL
The challenges of AL

AL is a young discipline and has many challenges ahead of it, including the following:
Analogies between AI and AL

AL is closely related to AI because artificial living systems can exhibit a certain degree of intelligence. In addition, there are certain analogies between the two disciplines. In several respects they can be considered complementary disciplines.
MENTAL and Artificial Life

Natural, Artificial and Abstract Life

A distinction must be made between three types of life:
  1. Natural (or real) life is the life of living organisms.

  2. Artificial life is life simulated by a computer, which is limited by physics (electronics). Artificial life can only reflect the complexity of the artificial physical world in which the organism "lives".

  3. Abstract (or formal) life is independent of implementation and is not limited because it belongs to the mental world.
Of these three categories, the most profound is the abstract, followed by the artificial, and finally the natural.

Similarly, one can also speak of natural physics (that of the real world), artificial physics and abstract physics. Artificial physics is that which can be simulated on a computer, it is physics as it is and as it could be. Abstract physics is independent of any implementation.

With respect to computation, three types must be distinguished:
  1. Natural computation refers to the way in which the laws of nature produce modifications in certain systems, which can be interpreted as computational processes. Natural computation includes, among others, computation with DNA molecules and cellular computation with membranes.

  2. Artificial (or physical) computing is computing on a computer, which is dependent on the hardware used and is constrained by the laws of physics governing the hardware. Computers of the von Neumann architecture, although inspired by the Turing machine, are of this type.

  3. Abstract or formal computation, which is implementation-independent because it is of the mental type. The mathematical operations we usually perform (the formal manipulation of symbols) are of this type. The Turing machine, which is a theoretical and abstract device, is also of this type. Paradoxically, computational processes (those that a Turing machine can perform) are called "effective" or "mechanical", even though they have no relation to the physical world.
Ideal computation is a computation in which there is an isomorphism between artificial and abstract computation. When isomorphism is replaced by identity we have computationalism (or computationalist philosophy). This is the case of a hypothetical computer whose primitives are the primitives of MENTAL. In MENTAL abstract physics, abstract mind, abstract computation and abstract life converge.

According to John Wheeler's "it from bit" theory, deep within reality is information (the bit). The known surface world (the it) is a manifestation of information. Computation belongs to the deep level of reality. The universe is a representation, map or superficial representation of a deep process which is computation. The universe is a computer that has been calculating for millions of years something that science is trying to discover.


Archetypes and abstract life

Language truly is the key to everything, as it is to consciousness. Life is the manifestation of consciousness over matter, the result of which is an organized and interrelated unity. Abstract life is based on the archetypes of consciousness.

The abstract archetypes of consciousness are universal and manifest on all planes of reality, including the plane of life. The manifestations of abstract archetypes allow us to generate abstract life in a self-referential, closed form, to generate autonomous forms. Biological functions are manifested archetypes.

By sharing the same archetypes, linguistics unites with biology. Any union must be made from the deep, from the archetypes.

The language of life is the same as for the mind and for nature: MENTAL, because it is based on the same archetypes of the consciousness manifested in these planes.

Regarding the question raised as to whether or not computational processes (which simulate life) are reality, it must be said that the computational is at a deep, abstract level, beyond the physical and mental. When the computational is expressed through the primary archetypes, we are at the level closest to consciousness, that is, at the level closest to life. Primary archetypes manifest at all levels. MENTAL is a model of mind, consciousness and life. MENTAL is a universal computer that manifests at all levels of reality. It is a universal model.


MENTAL, a language for AL

AL brings together many disciplines, but the best way to study it is through the mechanisms common to all of them, which are the primary archetypes. The advantages of this approach are:
The game of life. Analogies with MENTAL

The fact that the game of life generates such a diversity of possible forms indicates that it is something profound, close to an archetype. The deeper an archetype is, the greater are its manifestations. It is for this reason that it aroused so much interest and the reason that it has philosophical connotations. In this sense, it has certain analogies with MENTAL, because of its simplicity, because of the infinity of potential forms it can generate, because it is a computational model, and because it integrates information and environment. It also has an analogy with the mandala generation program, since simple geometric elements generate an infinite diversity of forms. Although in the case of mandalas the images are static.


MENTAL coding of the game of life

// We assign a value "0" to a dead (white) cell and "1" to a live (black) cell.

// c1 is the two-dimensional array of cells of n×n elements.

// c2 is the matrix at the next instant.

// initial values

(n = 1000) // half-size (horizontal and vertical) of the table of cells
(m = 1000) // number of iterations

(k = [−n…n]°)

[(c1(k k) = 0)] // initially set the matrix to zeros

( c1(00) = 1 ) // initial live cell configuration

...

display(c1) // display c1 on screen

⟨( neighbors(i j) = c1(i j+1) + c1(i j-1) +
c1(i-1 j) + c1(i+1 j) +
c1(i-1 j-1) + c1(i-1 j+1) +
c1(i+1 j-1) + c1(i+1 j+1) )⟩

// loop (m iterations)

[ (i=[1…m])

[i=k j=k

( (c1(i j) = 1) → (neighbors(i j) = ⌊2 3⌋) →

(c2(i j) = c1(i j)) )

( (c1(i j) = 0) → (neighbors(i j) = 3) →

(c2(i j) = 1) )

( (c1(i j) = 1) → (c2(i j) = 0) )

]

[ i=k j=k (c1(i j) = c2(i j)) ] // make c1 = c2

display(c2) // display c2 on screen

]


A criterion that can also be used to know if a stable configuration has been reached is to see if the c1 and c2 boards are the same.

Regarding the issue of the self-reproduction of a machine, this process is very complex if it is based on local, continuous transition rules. On the other hand, if it is based on non-local rules, the solution is discontinuous and very simple. It is sufficient to specify a transformation rule that copies the initial configuration onto another area of the board defined by the vector (dx dy).


Bioforms vs. Mandalas

Dawkins' bioforms have local developmental rules, i.e. the changes are small or gradual changes that occur from one generation to the next. From cumulative local changes can emerge a great variety of complex forms. The same is true of Conway's game of life, which also uses local rules and which can also produce many complex dynamic forms. The fact that such a variety of (superficial) forms are produced indicates that we are also dealing with something close to an archetype (deep).

The program (B) that generates the bioforms has certain analogies with the program (M) that generates the mandalas that illustrate this book:

Addenda

The foundation of the AL

The AL was officially born as an independent discipline in 1987 at the International Conference on the Synthesis and Simulation of Living Systems, also known as "Articial Life I" or "ALIFE I", held at the Los Alamos National Laboratory, in Santa Fe (New Mexico). It was attended by more than a hundred scientists from different disciplines such as biology, computer science, physics, philosophy and anthropology. The event was supported by the Santa Fe Institute, a private entity dedicated to interdisciplinary research in Complex Systems. LA AL is considered a research area within Complex Systems. The promoter of the meeting was Christopher Langton, who was the first to introduce the term "artificial life".

Langton has investigated CAs in their qualitative aspects by evaluating emergent behaviors. In this aspect, he has studied "Life on the Edge of Chaos" −title of his PhD thesis− in CAs based on the notion of entropy. He found simple (reaching fixed or periodic configurations in a few steps), complex (converging over long periods) and chaotic (producing no definite forms) behaviors. He postulated that evolutionary complex behaviors occur in a narrow range of specific circumstances. He has also investigated the topic of self-replicating machine models.


More about the game of life

Conway initially experimented the game of life with the help of the game of Go, which is a board formed by horizontal and vertical lines on whose intersections are placed white or black chips, corresponding respectively to two players. But soon personal computers were invented and he began to experiment with them. The game of Go also inspired Conway to invent surreal numbers.

The game of life became known in October 1970 in a column by Martin Gardner in Scientific American. The article aroused great interest. With the introduction of personal computers, people began experimenting with various initial forms, and many interesting structures were discovered: the pentomino; indefinitely growing patterns such as guns, which generate gliders; gliders; locomotives (puffers) that move and leave a trail of trash; rakes that move and emit spaceships; exploders; etc.

On May 18, 2010, Andrew J. Wade discovered a self-replicating pattern (which he named "Gemini"). This pattern replicates after 33.6 million generations. In each replication it eliminates the parent.

Many variants of the game of life are known. The standard game is symbolized by S23/B3 (2 or 3 neighboring living cells are necessary for survival and 3 living cells are necessary for a cell to live again). For example, the S16/B6 version indicates that a cell survives if it has 1 to 6 neighbors and needs 6 neighbors to revive. The S12/B1 set generates several approximations to the Sierpinski triangle when applied to a single living cell.

Versions with hexagonal or triangular mesh and with more than two states (which are represented by colors) have also been developed. Today there are hundreds of programs and online versions of the game of life.


Tom Ray and the AL

Tom Ray is a biologist who has been searching for the secret of the evolution of life in the real world. He first sought it in Costa Rica, studying butterflies and ants. But he found this research quite frustrating, as he wanted to be able to observe its effects on thousands of generations of organisms. He finally found what he was looking for in MIT's AI department. Ray's discovery was that programs can act like living organisms: interacting, self-replicating, undergoing random mutations, and passing code to their offspring. Ray learned genetic programming, and one day his first "digital creatures" were born. The space where these virtual creatures lived he called "Earth" (in Spanish), a computer simulation of the evolution of life, with mutations, inheritance and natural selection.


Turing and the AL

Alan Turing −who conceived an abstract device that we know today as the "universal Turing machine" capable of processing any algorithm, and which is the foundation of computers − was also a piner in what we today call "artificial life". He died when he was working on the computer simulation of biological development processes.


Bibliography