To define something is an indispensable first step to understand it. Thus, we should be aware that the complexity of the subject “abstract thought" starts from the difficulty of defining what is "thought " and what is " abstract ".

Let us begin by trying to define " thought ".

In Portuguese, we consulted The Aurélio's Dictionary. Leaving aside several definitions that explain absolutely nothing, like: "it is the act or the effect of thinking " or " it is the capacity to think logically ", concepts that, actually, leave us moving in circles, we got to find two that seem a little more reasonable:" it is a mental process that concentrates on ideas " and " it is the power to formulate concepts ".

In English, going through The Oxford Desk Dictionary and Thesaurus, we found ourselves again rotating around a same point, due to definitions like: "it is the process or power of thinking " or, worse still, "it is whatever somebody is thinking ", until we reached a more acceptable concept:"it is the faculty of reasoning” However, the definitons from these philologists don't satisfy the demands of philosophers, psychologists and neuroscientists.

But how do these people define 'thought'?

For Jung, "thought is a rational psychological function, that establishes behavioral relationships among representative contents, through the use of categories as ' true' or ' false', or as ' right' or ' ''wrong' ".

For Jolivet " thought it is the capacity that humans possess of knowing the meaning of things and the relationships between them". Because we admit that other species also think, we have a concept that, although, similar to that of Jolivet, is, in our opinion, less restrictive and more appropriate. Therefore, for us, " thought is the capacity that human beings possess, through three different mental operations: ' the ' formation of 'ideas', 'the judgement' about the relationships of convenience between these 'ideas' and ' the reasoning', that establishes relationships between 'judgements', to understand the meaning of concrete and abstract things, as well as the relationships they keep between themselves".

And what about the concept of " abstract "?

Let us return to the philologists:

In the Portuguese language, again in agreement with The Aurélio's Dictionary, " 'abstract' is what expresses a quality or a characteristic separated from the object to which it belongs or is linked to".

In the English language, again falling back upon The Oxford Desk Dictionary and Thesaurus, we have simpler concepts, such as: “abstract is what exists in thought or in theory and not in matter or in practice ".

Consulting other sources, scientific as well as philosophical, we obtained much more lucid concepts, which, although looking complex at first sight, actually allowed us, through related words, like ‘abstraction', ‘abstractness’ and 'idea', to define and understand, more clearly, what 'abstract' means.. ‘Abstractness’ is a concept in which one does not take in account a specific value, but any of all possible values related to whatever one is dealing with. For example, in algebra, when we say that x is a variable, we abstract ourselves from its present value, but we consider all the possible values of x as numbers, which are not `physical' objects, but linguistic objects formed by abstraction during the process of counting.

Mathematics is an ideal example of abstraction, since it does not ordinarily study the real world; instead it studies models that are abstractions from the real world. For instance: "three" is an abstract idea, not a concrete thing in the real world, but "three" is a very useful abstraction, because it allows us to be certain of how many "three" represents, and that adding one more will produce "four", whether we are talking about people, houses, bananas or any other thing.

There are other interesting and, sometimes, even contradictory considerations on this subject. Let us see:

According to the philosopher George Berkeley, abstract ideas are non entities, in other words, they don't constitute ideas that we really have but incoherent descriptions of ideas that we imagine to have. Thus, for him, ideas do not possess an existence of their own, always needing the presence of a being to perceive them. Such opinion contradicts that of the great philosopher Plato, for whom ideas (abstract or not) do exist, regardless of the existence of a human mind to notice them, since they do not start inside us, but they are already out there, in the universe, conceived by a Superior Being.

Allan Randall, who partially agrees with the Greek philosopher, states that, since the abstract idea possesses its own existence, we must imagine it as an idea of some specific thing. And he explains: if, for instance, we 'abstract' or remove, an apple from the real world in which that apple is located, we are left only with a very particular idea - that of the word ' apple'. The idea, in itself, although obtained through an abstraction, it is not inherently abstract. It is, actually a particular idea of something concrete. In this case, a type of mental image of an apple with definite color, shape and size. Abstract idea, that reached its highest degree of development in our species, became the source of creativity. Without it, the human race would had been deprived of one of the most beautiful expressions that life can provide: art. As, by definition , the ' abstract' must have no mass, shape, size and color, almost all works of art are definitely concrete. Let us take as example an original painting, not a copy. of course. It resulted from an initial abstract conception of the artist's mind, from which he built a certain image and painted it. Thus, his work became concrete, because it has mass, color and dimensions.

On the other hand, the music of a song, another beautiful artistic creation, is deprived of color, mass and dimensions. Therefore, by definition, it would be an abstraction. However, music is captured by one of our sensorial perceptions: the auditory. Therefore, from our viewpoint, music does not represent a pure " abstraction ". Thus, we rather consider it a semi-abstraction or partial abstraction, limiting the concept of " pure " or absolute abstraction for those that, besides being deprived of color, mass and dimensions, are not also noticed by the sensorial organs. They are just "felt" by the mind.

As examples of absolute abstraction, we have feelings, like jealousy, passion or wrath, love or hate, happiness or sadness, all of them deeply imbedded inside the neurons of our limbic system or, as John Eccles would say, in the depths of our souls...

Later on, we will refer to other examples of absolute abstraction.

It is also quite important and significant, for the understanding of the process of thought, in general, and that of abstract thought, in particular, the concepts presented by James D. Weinland in his book How to Think Straight. For this author " thinking is a mental activity of a trial and error nature that precedes physical action. It occurs when the next step to be taken is unknown because some difficulty interferes with action. In such cases imaginary trials point the way to a solution, thus preventing unwise responses".

This definition brings to the mind, another one, by the famous Russian neurophysiologist Aleksandr Romanovich Luria. According to him, "thinking arises only when the subject is confronted by a situation for which he has no ready-made (inborn or habitual) solution ".

In the conception defended by Weinland, thought is a complex act, in which we can isolate the percepts (that is, the impressions of an object obtained by our senses), the concepts and the generalizations, related to each other by induction and deduction, subject to the action of subordinated processes, such as classification and formulation of hypotheses.

From Weinland's definitions, regarding the different constituent elements of thought, we may conclude that only the percepts have a concrete and individual character, since they refer to information captured by the different sensorial organs and its analysis by the corresponding cortical centers. The author also points out that, “although they constitute fundamental units of thought, percepts are not the most elementary mental experiences of human beings”, because they are “a compound consisting of sensation and memory".

In the elaboration of concepts or ideas, what is non concrete, what is grupal, tend to prevail, since they are formed by a series of several individual copies of objects and beings, from which, through abstraction, one eliminates the differences and keeps the common qualities.

Still according to Weinland, concepts can be classified as being of high or low level. “Low level concepts based on actual percepts of individual things,come directly from personal contact with things and help to form our practical experience ". On the contrary, high level concepts are less dependent upon the experience of any one person. They derive, in a large part, from education and, therefore, are related to the culture of our civilized world. In other words, of the universe in which they are inserted.

Concepts are related to each other by generalization, an abstract activity that identifies existent similarities.

The importance of abstraction in the formation of thought was already pointed out centuries ago by authors as Condillac (apud Cuvillier) who, in 1798, affirmed that the abstract process begins at the phase of perception, since, “actually, our senses decompose each object ".

Laromiguiere (apud Cuvillier), at about the same epoch and following a similar line, said that " our body is a machine of abstractions ".

Therefore, abstraction can be understood as a reducing and simplifyng analysis of the complex sensorial -perceptive world we live in, promoting the bases of thoughts that allows us to make the appropriate decisions, in order to guarantee our survival as individuals and species.

The Neurophysiological Substrata of Abstract Thought

The concept of functional units of the brain, as proposed by Luria is a very important knowledge for understanding the neurophysiological substrata of abstract thought. According to him, the several structures that make up the brain can be considered as constituent parts of three main functional units:

1. An unit responsible for regulating the state of cortical activity and the level of vigilance. It is formed by the reticular substance and other structures located in the brainstem, the diencephalon and the medial regions of the cortex.

2. An unit for the reception, analysis and storage of information - constituted by lateral regions of the neocortex, situated at the convex surface of the cerebral hemisphere. They comprise the occipital (vision), temporal (audition) and parietal (general sensibility) areas.

3. An unit for programming, regulation and verification of activity - formed by structures located at the anterior regions of the cerebral hemispheres, anteriorly to the paracentral gyrus.

For Luria, thought in general depends on the coordinated action of these three functional units. However, the last two seem to have greater importance as far as the abstract component is concerned.

The second functional unit, as it was already mentioned, is formed by the occipital, temporal and parietal regions. Three anatomical and functionally different areas can be distinguished in these regions.

a) Primary or projection areas - formed, mainly, by neurons of the so-called afferent layer IV . Many of those cells display a high degree of modal specification. They receive the fibers coming from the sensorial organs and analyze their specific information.

b) Secondary or gnostic areas - intimately related with the primary ones and constituted, mainly, of neurons from the cellular layers II and III, which are endowed with smaller degree of modal specification. The presence of a large number of neurons with short axons enables incoming stimuli to be combined with each other, thus creating a local neuronal web pattern, capable of accomplishing a synthetic function.

c) Tertiary (or overlapping areas of the cortical ends of the various analysers)- composed almost entirely by neurons of the associative layers II and III. They have the capability to integrate and analyze, simultaneously, a large amount of information arriving from several regions of the brain. These group of neurons are located in the inferior parietal zone, situated among the occipital, temporal and postcentral cortex. By comparing the brain of several animals, one finds that this particular zone acquires its maximum development in the human species.

The tertiary structures are located at the following classic areas, as described by Brodmann: 5, 7, 39 and 40 ( parietal area), 21 (temporary area) and 37 and 39 ( temporo-occipital area).

These areas are in charge of integrating the incoming excitations from several analysers. According to Luria their main role is to promote the spatial organization of afferent impulses arriving from different analysers and to convert “the successive stimuli into simultaneously processed groups, the only possible mechanism capable for that synthetic character of perception. which Sechenov originally discussed many years ago".

Still according to Luria, these areas " play an essential role in the conversion of concrete perception into abstract thinking”.

Abstractions, formed in the second functional unit, are used by the third unit for programming all kinds of activities. Of special importance, in this third unit, are the prefrontal areas, formed by granular neurons, that maintains two-ways connections with the diencephalon, the brainstem and with almost all other regions of the cortex. The prefrontal areas, that reach their maximum development in our species, play a fundamental role in the formation of intentions and programs, as well as in the regulation and verification of the more complex human behaviors.

Lesions in the tertiary areas of the second functional unit provoke several neuro psychological alterations, like the incapacity of capturing the global sense of a verbal construction, although preserving the understanding of individual words.

The patient is capable to understand communications of simple events (for instance, dad and mom went to the movies), but he can not capture communications linked to relationships (for instance, a lady went from the factory to the school where Nina studies, in order to give a lecture). And he also gets “confused when facing expressions like "much larger than" or “many more times”.

On the other hand, lesions in the tertiary areas of the third functional unit, that is, in the prefrontal areas, give rise to several motor dysfunctions and cognitive alterations, since the patient is no longer capable to program his activities and analyze his performance.

Lhermitte (apud Miller), studying two patients submitted to extensive ablations of both frontal lobes, observed that they became unable to capture the global meaning of a social situation, answering only to details of it. This led that author to coin the term “syndrome of environmental dependence” to describe that type of deficient behavior. According to Laurence Miller, these patients are “virtual slaves of isolated contextual cues”.

Although there is no general agreement, we believe that other species are also capable to develop abstractions. Some primates and cetaceans, without any doubt, have abstract conceptions, but these must be very tenuous and, certainly, they never develop, as humans do, to a point of giving rise to high creativity. And, even if it so happened, it would be an innocuous creativity, since they lack the physical attributes to allow them to build up something that could be considered significant and concrete. In spite of these handicaps, the exercise of conscious and abstract thoughts, among dolphins and superior simians, has been widely evidenced.

Premeditation, although of little acts, conjugated actions and rationally conceived cunning are behaviors that necessarily involve the employment of abstractions.

It must be stressed that we are referring to a type of cunning derived from logic, not from intuition. The intuitive cunning is, in variable degrees, inherent to all animals, since it is an important instrument in the mechanisms of survival of beings and species.

The famous studies accomplished by Wolfgang Kohler in the Canary Islands clearly demonstrated the use of rational cunning and conjugated actions by superior monkeys. Among the countless observations led by this scientist, there is one that, not only due to its humorous aspect, but also because of the existence of a definite abstract component in the process, deserves to be mentioned here. It has to do with the malicious and wicked attitude practiced by two male chimpanzees against a chicken: one of the monkeys presents a food to the fowl, encouraging it to approach. As soon as the chicken gets close enough, the other chimpanzee hits the fowl with a wire that he had maintained hidden behind his back. The chicken retreats but soon falls again in the trap, since its mind is not capable to establish association between the offer of food and the following blow. And the game goes on and on, until the monkeys, possibly tired of their joke, move away from the stupid gallinaceous. The abstract component is denounced by the evident forethought of an elaborated conspiracy, executed, in an united action, by the two chimpanzees.

The abstract thought may develop from external stimuli captured by the sensorial organs, from evoked memories or, simply, from incoming messages hidden in the depths of the mind and without any trace of a conscious memory. It was as if they had just appeared from nowhere!

However, independently of the origin of the stimulus that triggered the mental process, abstract thoughts represent ideas or feelings, without shape, size or color, like love, passion, hate or sadness - limbic abstractions, or something like ethical and moral sense, or planning future actions. - neocortical abstractions.

Also, the ability of the mind to select a novel route or a new way to reach a certain goal has definitely to do with abstract thought. Sometimes, the abstract thought, just like the spatial conception of something - possibly processed somewhere in the right hemisphere, acquires a three-dimensional character. This allows the mental process to develop towards a more defined type of creativity, in other words, one type of creativity that, starting from the intelligent association of abstract ideas, " builds " a three-dimensional thought that permits the conception and, eventually, later on, the construction of new concrete things.

In other instances, the initial abstraction generates new concepts, equally abstract, but that evolves to the formulation of physic laws of the highest practical sense. It is the case of Hilbert's geometric conception about the interception of parallel lines, that became the basis of the gravitation theory elaborated by Einstein.

Or the idea of that same mathematician to " build " multidimensional abstract spaces, through the application of simple mathematical functions that, 25 years later, was to become one of the foundations of quantum mechanics. But abstract thought provides something more: when involved in a creativity process, it acquires such a magnitude that ends up being a very strong stimulus, capable to promote the proliferation of dendrites and axons, thus creating many new synapses. In this way, abstract thought must be considered as a powerful stimulant for learning, knowledge and memory formation.

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The Authors
 

Jorge Martins de Oliveira, MD, PhD  MD, PhD. Full Professor and Master of UFRJ (Rio de Janeiro). Associate Professor of UFF. Scientific Coordinator. Coordinador and Director of the Department of Neurosciences of the Institute of Human Being (RJ). Fellow in Research by Saint Vincent Charity Hospital, Cleveland, USA. Full Member of Brazilian Academy of Military Medicine. Member of the Brazilian Academy of Writers Physicians. Graduated by Superior School of War (ESG). jmartins@rio.nutecnet.com.br

Júlio Rocha do Amaral, MD - Teacher of clinical pharmacology, anatomy and physiology. Medical Manager of Merck S/A Indústrias Químicas (pharmaceutical and chemical industries). Redactor of didactic manuals on anatomy, physiology and pharmacology used by Merck S/A. Editing supervisor of the following scientific publications: Senecta, Galenus and Sinapse. Redactor of clinical trials and protocols since 1978. Assistant coordinator of courses on Oxydology sponsored by the Human Being Institute  and UNIGRANRIO (University of Great Rio). Head of Psychiatric Service. Neurosciences Department. The Human Being Institute. Co-author of the book "Principles of Neurosciences" Email: julioamaral@pobox.com