In this post we focus the issue of the evolution of species, also trying to resolve the dispute between evolution and creationism, a debate that is still very much alive in the United States of America because of religious beliefs; here we follow a point of view both scientific and philosophical. We will use an approach that I think has not been used so far, based on physics, understanding the true meaning of chance, and also, of course, in chemistry, but everything at basic level without technical complications.
Early Evolution: cells
By a random process combinations of chemical elements, at some point on past in Earth organic molecules was produced, among which were generated complex proteins named enzymes and DNA, key to accurately replicate a living being, which seen from the perspective of Biochemistry, is a self-made and complex system self-maintained by precisely regulated biochemical reactions. DNA has billions of years; evolution, as we know, did not stop with the generation of "smart" molecules, but continued to generate more and more complex systems.
The generation of the first primitive cell still unsolved mysteries for science, because it does not exist, can not exist, fossils of cells to be studied, because the cell is too "soft", so to speak, for to leave no trace over millions of years. We must assume, and so does science, that spontaneous process described in the other articles in the series continued to generate more complex systems and to eventually generate cells, that is, not just systems complex biochemical but living beings.
In any case, the "blind creator" (random combination) has a clear direction: generate more complex beings who have a biochemical machinery capable of self-regulation and self-replicating. These two features, although in lesser extent, were already present in proteins and DNA, so that consider a biochemical system as alive or not alive is rather a matter of degree of self-regulation and self-replication and also about "intelligent" interaction with the environment. There is no clear dividing line; it is known that viruses, which are only specialized in parasitize cells DNA, are in a limbo between the living and nonliving, are in no man's land, according to our clear concepts, so because commented inability to draw a line clear dividing.
Evolution of the species
The "tendency" to generate complexity from simpler components, by the mechanism of mixing random, letting emerge new systems, which can last over time or not, did not stop in the cell, but I went ahead, even more strongly, linking cells in cell colonies, later in various multicellular organisms; to the various cell combinations that share the same structure, encoded in DNA, we call species. Thus, the tendency continued to generate random species, some persisted, many, most, became extinct.
Then, in the evolution of species enters a new factor: natural selection (Darwin's great contribution); this is so because the DNA is programmed to generate an exact copy of the individual, maintaining the species, so the random generation of new bodies would end simply primitive species had been playing no more, no evolution. But it happens that the playback mechanism DNA, being very accurate, is not perfect, occasionally errors, producing mutations occur; these mutations are the origin of new species. The mechanism that "decide" whether a new species must replace the old or is not called natural selection. Thus the enormous diversity of life we see around us is explained by these two mechanisms: the biochemical machinery reproductive DNA and random errors, and natural selection pressure, that "decide" which species will endure.
So far we have been following in the footsteps of science, from the creation of first cellar in the ancient Earth to the Darwinian evolution of species. Even today there are still doubts about this scientific theory, partly because of religious beliefs, partly because of unbelief, because for some people seems impossible that the mere chance has generated everything around us. The positions are closed: people are on one side or the other, so that discussions on this topic are often on, more like a boxing match than an exchange of views. This blog is not devoted to religious themes, but if scientific and also philosophical ones, so let's dare to give our opinion, and we give our attention to such matter of random creation, a prodigiously creative and intelligent process without no doubt. Let me jump momentarily to the field of Physics.
Light was not, after all, neither waves nor particles
The nature of light was another debate that lasted centuries, indeed millennia since the first theories date back to ancient civilizations. Descartes postulated light was composed of a beam of light particles, and thus was able to explain the laws of reflection, but had problems with refraction; Newton also completed the corpuscular theory explaining the laws of refraction, but could not explain the phenomenon of interference. Huygens, a contemporary of Newton, he was also able to explain the observed phenomena were assuming that the light waves, not particles, but because of the enormous prestige of Newton was not taken into account at that time. Not much later experiments of Thomas Young seemed to tip the balance towards the wave model, especially when Auguste Fresnel gave him the mathematical precision theory, but still continued having distinguished scientists who still believed in the corpuscular theory, as Brenster in England , Laplace, Biot and Poisson in France.
The controversy seemed to be settled with the electromagnetic theory of J.C. Maxwell and Hertz's experiments: the light was indeed a wave of electromagnetic nature. Already in the early twentieth century wave theory stagger again with the discovery of the photoelectric effect and its theoretical explanation by Einstein, again based on the particle nature of light. So, it was an enigma, as some phenomena were clearly explained by the corpuscular theory, and others by the wave. The solution came from the hand of Louis de Broglie, who proposed that the true nature of light was neither wave nor particle, but both at once, so that was presented in one way or another is something depends on the experiment.
Debate random creation and evolution against creationism and intelligent design
Returning to the topic, in the genesis and evolution of life we have another debate: on the one hand observations and evolutionary theories based on pure chance are agree, but on the other hand we have a credibility problem, because if we speak of chance we can speak of probabilities, and that whenever there is a random process, which may arise mixed results so unpredictable principle, we can, at least in principle, properly speak of the probability of occurrence one or the other result. It is extremely difficult, if not impossible, to accurately calculate the probability that, out of nowhere, appeared a Universe like we have, and within it, life appeared and evolve to the current diversity, but we has made some attempt. Roger Penrose made a rough estimate that from the Big Bang explosion appeared a stable universe, look at it is only required to be stable, that is, that does not consist in a "soup" of radiation where matter and antimatter destroy each other, and then reissued in an endless cycle, where the matter could never survive; this probability is about one in between 10¹²⁸ ... this value is incredibly close to zero, is a zero comma ... a hundred and twenty seven zeros and then, the number one:
0,000000000 ...(a hundred and seven more zeros)... 000000001
This data makes us doubt that the current Universe is generated uniquely by a random process; I do not know any similar calculation for the probability that the primitive cell was created from inert material by mere chance appears, but knowing that even a cell is an organism of incredible complexity, seems clear that the probability is of the same order or even lower. Given that the probabilities of successive independent events are multiplied together, we find that the probability that this stable universe appears, then life in it, would be the product of an amount practically nil otherwise also negligible, and the score much smaller than any of the above, as is evident if we consider for example that 0.1 x 0.1 = 0.01, or 0.01 x 0.01 = 0.0001.
To answer this riddle of probability virtually zero people usually go to the anthropic principle, let me explain it: when Science faces with inconvenient questions, simply is renouncing to answer them, merely answering what Science really do belongs to its sphere of knowledge: observe nature, discovering regularities of behavior, and try to describe these regularities with an exact language. For example, the response from Stephen Hawking to the question "why the laws of the early universe were these and not others?, we know any small change in them, if only one hundredth of 1% would have made impossible the existence of universe and life as we know it" is "we see the universe the way it is because we exist".
Not only random evolution or creationism or intelligent design only, but both
The proposal given here to resolve the debate is to take a position similar to that solved the riddle of the nature of light: the creation was not only entirely random nor entirely intelligent creation, but both, coming to light one aspect or another depending on how we look. Indeed there is a random process acting on a "building materials", generating new elements, but there is also something else that marks an arrow, a vector, a direction, towards complexity and stability of creation. Otherwise the dilemma of zero probability has no answer. To understand it better, we deepen a bit on the true meaning of the word random, their concept associated.
In Quantum Physics randomness is an intrinsic property of Nature, but in Chemistry is not, instead, all the chemical reaction are causal: the products are obtained from the sources, given a set of conditions, in a well defined way. So, if we are speaking about randomness related to the field of Biochemistry, indeed we are talking about a combination of unforeseen circumstances that exist previously, unpredictable for us but they are there, acting, and combining with each other to produce definite results.
The is always linked to a fact or event, "something"; so we have a "something" and their circumstances, which are combined together unpredictably. What is that something underlying? What we are pointing out here is that whenever we speak of the action of randomness as an explanation of a phenomenon, we are actually stating that there is something that manifests itself in the form of circumstances that, for us, are unpredictable, we can not predict, a priori, its manifestation, which however occurs. Therefore "explain" the whole evolution shrugging, saying "it's pure randomness", and nothing else, is in fact an abuse of language, that randomness is not an explanation of anything, it's just a form of manifestation of somewhat, which it can be foreseeable or unforeseeable. And this is not "philosophy" is simply knowing the true meaning of the words we use.
Thus, the thesis advocated here, in brief:
- There is a "something" underlying, inherent, pre-existing, in all the creation of the diversity of life
- That something evolves by random interaction of its various manifestations
- In that randomness however there is a predetermined direction leading to increasingly complex manifestations, producing cells from proteins, and complex life from cells; seeing the results of such direction, in some way we can name it as "intelligent direction", because produce high ordered complexity.
- Contemporary Science, pragmatically, empirically, traditionally is not been able to access that something that manifests, has only had access to the results of the demonstration, has seen only randomness, and renounced go beyond; this is perfectly right, but trying to extrapolate, as many scientists do, this limitation of science pretending that nothing more exists because science can not see it is wrong.
- The combination of scientific knowledge with philosophical thinking can lead us to a better understanding of creation and evolution of life.