Chance, design and artificial life

In previous posts in this blog I have mentioned my experiments on artificial life: the simulation in a computer of processes similar to those that take place in living beings. Artificial life should not be confused with synthetic life: construction of artificial living beings in the laboratory.

One of the most used tools in artificial life (and in other related fields) are genetic algorithms, which simulate biological evolution within the computer, and make it act on the entities that are the subjects of the research. In these experiments, a mixture of chance and necessity (the title of Monod’s book mentioned in the previous post) is used. Chance is usually applied with a pseudo-random number generator that modifies the operation of the rest of the algorithm, which represents necessity.

Different types of chance

Jacques Monod

When we don’t know why something happens, we usually say that it is due to chance. But this statement is ambiguous, because there are two different types of chance:

• Epistemological chance, where the cause of what’s happening is well-known, but so complex that it remains outside the scope of our knowledge. Almost all games of chance (dice, roulette, lottery jackpot) are examples of this type of chance. Rolling dice conforms to the laws of mechanics, but the conditions are so complex that we cannot predict the result of each roll. This type of chance is what Jacques Monod called operational uncertainty in his book Chance and Necessity (1970):

This term is used... in relation to the game of dice, or roulette, and the calculation of probabilities is used to predict the result of a play. But these purely mechanical and macroscopic games are not "the result of chance" except because of the practical impossibility of controlling the throwing of the dice or the ball with sufficient precision. It is evident that a very high precision launching mechanism is conceivable, and would make it possible to largely eliminate the uncertainty of the result... The same thing happens, as will be easily seen, in... many phenomena where the notion of chance and the calculation of probabilities are applied for purely methodological reasons. (My translation into English).

A new fine-tuning case and the “great design”

Almost every case of fine-tuning discussed so far concerns nuclear reactions and their consequences, in the realm of the very small. This is what could happen if the universal constants and parameters were not fine-tuned:

• Either there would be no hydrogen in the universe, and the stars would last too short a time for life to appear.
• Or the fusion of hydrogen to give helium would not be possible, so there would be no stars.
• Or oxygen or carbon, essential elements for life, would not be generated in stars.

In all these cases, concepts and ideas are drawn from particle physics, astronomy, and cosmology.

Chance and certainty

In a comment to the Spanish version of a previous post of mine, JL advised me to read the book entitled Chance and Certainty, by Georges Salet, who wrote it to prove that the origin of life and its subsequent evolution are impossible, if we apply the calculus of probabilities. In addition, he challenged me to refute at least one of the arguments proposed by the book, in the following words:

The work contains hundreds of arguments and demonstrations; if you, or anyone else whose help you ask, are able to refute a single argument or demonstration, I will readily admit that life can indeed arise spontaneously.

Salet's book is out of print and very hard to come by. I am grateful to another comment contributor, who provided me with the opportunity to read this book. I can therefore accept JL's challenge.

Chance or pseudo-chance?

Gregory Chaitin

In computer programming, certain algorithms (called pseudo-random) generate series of numbers that meet the conditions required by statistics to decide on the randomness of a sequence. These algorithms are used frequently to simulate chance.

However, these algorithms have been designed by someone (the programmer who invented them). In fact, they are not usually random, in the sense that, if they are executed several times in a row, they always give the same results.

We have a similar case with the digits of p. Ten trillion digits of p are currently known, and their number is constantly growing. So far, the digits of p have met all statistical randomization tests. However, it is evident that they cannot be truly random, that they are designed. There are simple algorithms that generate them one after another, in the correct order.

Let us go back to the mental experiment of the previous post in this blog. If intelligent beings were to emerge in an artificial life experiment,

Would these beings be able to distinguish between chance and design as the origin of their own existence?

Chance or design?

Tree of life

In this context, we must distinguish three things:

1. The scientific theory of evolution, which is strongly supported by data from other sciences, such as embryology, comparative anatomy, paleontology, biogeography, or molecular biology (DNA analysis).
2. The claim that evolution is a consequence of pure chance, which is not a scientific theory, but philosophical, although its supporters claim that it is scientific.
3. The assertion that evolution is an example of design, which is not a scientific theory either, but philosophical. The supporters of intelligent design argue that it is scientific.

To solve this dilemma we would have to answer one of the following questions:

•         Is there a way to prove scientifically that evolution is a consequence of chance, rather than design?

•         Is there a way to prove scientifically that evolution is a consequence of design, rather than chance?