(Note 52. Evolutionist Treatise of Biology). Part Two. Volume I, pp. 309-314)
Scientific work seeks to use a monist interpretation of reality that is as complete as possible: it seeks to explain any type of being or phenomenon in terms of the rest of reality, unravelling the relations between things and seeking to express them in increasingly inclusive laws in the belief -which seems to be both the principle and the corollary of science- that the universe is a coherent whole whose process can be gradually discovered.
Thus understood, a strictly monistic interpretation of anything at all (say, for example, a living being) seems impossible, because understanding it fully would mean knowing everything, which is beyond the feasible scope of humans in the entire course of their finite existence on a cosmic scale. Consequently, monism -the rationally progressive way to understand nature- has no meaning other than in scientific research, in which a clear presentation of the problems, of the limits of knowledge, is essential.
Hence, the scientific investigation of nature appears today to be an unlimited process of thought. To avoid going astray, it must be divided complementarily into two systems of knowledge: the system of what we know or what we think we know, with various degrees of certainty, and the system of what we do not know, with the corresponding depth of our ignorance. I think that systematizing the science that has been done without taking into account the corresponding ignorance poses a serious risk of making idealist interpretations that are based on two incapacitating, anti-scientific errors: latent dualism and dogmatism. It is thus correct to say that a scientist, and in general any rational man, is a professional of ignorance, which he gradually pushes aside.
In accordance with the above, it seems that we should state clearly the most general property of reality -independent of any other- that can be deduced from our knowledge, and we must consider it as what it undoubtedly is: first, it is the strongest and most general basis for the development of future knowledge provided by our interpretation of nature according to the most general and truest theory that has been achieved so far, and we must improve it by correcting and refining it; second, it is the description of the current limit of our monistic interpretation of nature, which at some time will in all likelihood become an obstacle to the further development of science until it is superseded. Consequently, stating this basic problem clearly has two major advantages: first, it allows us to orient the specific problems in the proper perspective on the basis of the unitary theoretical system that is most in line with the overall coherence of reality; second, it will prevent this basic problem from being erased from view and therefore from being incorporated as dogma and diluted into accepted science, thus contaminating our interpretation of reality with dogmatic dualism.
To define this basic ignorance clearly, it seems advisable to trace its origin from the previous ignorance, from which it naturally stemmed, and which to some extent it satisfies. Let us therefore analyse the limit of the knowledge that, in the guise of an absolute epistemological basis, has conditioned the development of the experimental sciences. I believe that it is the Aristotelian concept of matter that still prevails in much of science, and in particular in biology. The aim is to prevent our evolutionary interpretation from falling into dogma; i.e. the ultimate conclusion of our thought should appear as it really is: a problem of a new type whose resolution must allow a further expansion of science that will go beyond it.
Aristotle formulated monism and prepared the logical tool for implementing it. With exemplary consistency, he reacted to Platonic dualism and strove to understand reality by observing it and analysing it directly, so no one has a fairer claim to being considered the father of science and, in particular, of scientific biology. Like everything human, Aristotle's memorable feat could not go beyond the limit of the thought and state of knowledge of his time. It was objectively impossible for him to shed Platonic idealism, and his unfading merit was to place it at the service of scientific materialism. For Plato, ideas had a primary, supernatural life, and material beings were merely an imperfect reflection of them: simulations of true existence. Aristotle, on the other hand, thought that Platonic ideas took refuge in the underlying forms within matter as something immanent that is only realized fully in matter, as an entelechy.
In short, Aristotle made a memorable change of thought (and took the first vigorous steps in the direction he laid down), which, for historical reasons, was only fully developed twenty centuries later with the birth of modern experimental science. From my scientific viewpoint, this turning point of Aristotle can be characterized as follows: it established scientific monism, i.e. it considered that nature can be explained progressively by itself, and that the key to beings can be sought within them, in their inner structure. I believe that the first of these two concepts shows an increasingly profound basis of truth. The second also has an enormous basis of truth, which is evident in the enormous analytical or anatomical conquests of experimental science. It is, indeed, general knowledge that the most varied materials of both inorganic and biological origin are composed of molecules, that molecules are composed of atoms, and that atoms are composed of subatomic particles. In biology, too, the most varied regularities of internal organization have been observed in animals, in plants and in single-cell beings, and have led science to seek the key to their structure in their interior. (It is clear that some of these biological regularities of internal organization are so general that they must indicate something very profound. For example, all animals and plants are composed of cells; in the interior of all cells there is enzymatic activity linked to proteins; all proteins are composed of L-α-amino acids with the same steric composition; in cell reproduction the chromosomal material of the nucleus plays a general role, etc.).
The Aristotelian form immanent in matter has been revealed in entities that are increasingly differentiated and better understood. However, experimental science has also discovered the general process (gravitational energy, thermal energy, electromagnetic fields, radiant energy, the transformation of matter into energy, etc.) and, finally, the fact of biological evolution. All of this indicates that the Aristotelian basis of experimental science, which is that the key to the being is in its interior, is today an epistemological basis that must be overcome before it turns into a dogma that immobilizes science.
Aristotle 384 BC - 322 BC
In my view, the monism of Aristotle (who brought attention back to the nature that is knowable through its analysis by applying the right logical tool) achieved a memorable progressive change with the discovery of genuine units, elements that each belong to a higher order and stratify reality into certain integrative levels. It was the discovery of some of these levels (animals, cells, molecules, atoms and subatomic particles) that gave rise to the various modern experimental sciences. (In my book La función de la ciencia en la sociedad (Spanish), I try to understand how empirical knowledge, increasingly rigorous and precise, was transformed into modern experimental science, which can be theorized, and to discover the meaning of modern experimental science in the progress of thought). Each of these sciences focuses on the study of one of these levels of reality (for example, chemistry studies molecules), describing the properties of the units of the various types that occur in it, examining their composition and the internal structure of each unit of the immediately lower level, the transformations of some units into others within the level, etc. In our view, what is truly remarkable about the experimental sciences for the interpretation of the universe is the fact that each of them not only perceives regularities (which can be described and classified and thus enrich human activity, in the same way as the regularities of nature help the action and experience of living beings), but these regularities begin to be explained, according to laws and theories of increasing scope, not only because of the composition of the units of each level in sets of units of the immediately lower level, but also because this composition depends on reversible interactions with units of the same level in the environment.
Thus, it gradually became clear in science that in order to understand the units of a level (subatomic particles, atoms, molecules, cells and animals), one must both analyse their interior and study their interactions with the units of the level. What is more, one must theoretically correlate the two types of data -and in particular the internal dynamism of the units of a level- with the overall dynamism of the level that relates units with each other. (In my opinion, the only guarantee of obtaining objective knowledge of levels of reality which cannot be directly observed by our senses is precisely a theoretical thought that is increasingly unifying, better foresees results before they are verified and, in general, is built in a constant struggle with prejudice). It is logical that humans perceive the relationship between a unit of any type and its general level first and foremost in relation to their own individuality (the content of their awareness) and their particular, coherent medium: society. This crucial change in the progress of experimental science (in which Aristotelian monism, seeking to find the explanation of units in their interior, discovered that the key to the internal process is in turn found in the general process of the level) also provides the biologist with a supplementary interest: understanding the regularities of the biosphere that make possible the action and experience of living beings through the general process of the levels.
Thus, the general evolution of reality seems to be a corollary of experimental science in which this science preserves and supersedes its Aristotelian basis. According to evolution, all natural phenomena must be related to the units of the appropriate level and these are explained (and explain the phenomenon) in terms that are perfectly coherent with the rest of nature (both the lower levels and their own level, which are in turn determined in some way by the process of the higher levels). In accordance with this concept, the aim of this book is to try to explain, as coherently as possible, a space-time sector of the evolution of the universe, i.e. biological evolution on Earth.
How do we understand biological evolution to have occurred? We can deduce from the experimental data of the interior of the individuals of each level that they consist of a soma formed by a set of individuals of the immediately lower level cooperating in a series of unitary actions, and an organism that is a unitary physical field in which the experience of each of these actions is exercised. In turn, this physical field results from an integrated effect produced together by the closely cooperating organisms of living beings belonging to the soma of the living being in question. This physical field of each organism is limited in space and time; it receives the afferent stimulus of the previous action and responds to it by applying a quantum of awareness and freedom. Now, I think that the goal of biology is to specify, in terms of biological evolution, the internal qualities (resulting from a soma) and the external conditions (confronting the evolving whole through the organisms of the immediately lower level) that a circumscribed physical field must have in order to constitute the focus of experience, to acquire that outstanding capacity of awareness and freedom (which we perceive directly through our own), and to determine the scope of the experience of each living being.
In conclusion, the action and experience of the units of a level (with the quantum of awareness and freedom that performing them involves) require the action and experience (with the resulting awareness and freedom) of the immediately lower level, which require those of the immediately lower level, and so on. When organisms of a new level, i.e. physical fields circumscribed in space and time (necessarily of the same physical nature as a general, inorganic physical field) emerge in reality, they must result from associations of individuals of the immediately lower level that emerged from the general evolution of that level, and through these associations they must be confronted with a trophic level in the environment that they were heretofore unable to exploit, governing the corresponding type of new medium. It therefore seems that they must have had the capacity of experience, i.e. of awareness and freedom, which allowed them to perceive the effects on the new medium of the cooperating activity of the individuals of the lower level that formed their respective associations and to try out a reaction of their own that indicated to these individuals the appropriate change of the next cooperative action. Thus, these subordinate individuals must apply their awareness to perceiving the indications of the higher organism and their freedom to obey them because they are useful.
We can therefore say descriptively that the awareness -and resulting freedom- is a general property of the given reality, with its corresponding modality, at all integrative levels. When fields circumscribed in space and time emerge on the lower level, they actualize a faculty that has somehow been latent, performing another function, in the general physical field of the same nature and, furthermore, in the primordia of all organisms. What this universal property of the general physical fields is, and how it is actualized as awareness in the units of all integrative levels (set against the evolving whole), is a problem that seems beyond the theoretical horizon of evolutionary biology -at least of my own- and one that biology poses to physics. Solving this problem may contribute to a more unifying interpretation of the universe (in which the awareness results from another general property) and may also allow a future qualitative step forward in the understanding of the living being.
I therefore wish to specify that this indication that awareness and freedom are a general property of the defining reality of the individuals of each of the successive levels -not only biological but also cosmic agents of evolution- should be considered a basic corollary of biology that we deduce from its scientific development but cannot yet include in it. In other words, we can relate the faculty of experience of the organisms of a level to that of those of another level, but we cannot account for it through the property of all fields that are circumscribed, which necessarily depend on a general property of reality and, above all, on their own primordia. I think that this is a an absolute limit for me, and perhaps for science at the current level of development. However, it should it should not be a limit for future progress, which should consciously seek to overcome it, to prevent a new version of dualism (the resistance opposed by what is thought to be known but is not known) from surreptitiously emerging and blocking the progress of thought for a time, as Aristotelian thinking, so fruitful and veracious in its time, is now doing.