René Descartes' valuable contributions to Psychology

Rene Descartes was a typical example of a Renaissance intellectual: soldier, scientist, philosopher and speculative psychologist.

He studied with the Jesuits, and his training was both metaphysical and humanistic. His influence has been decisive in his reformulation of the rationalism, and including him in a system mechanistic.

Descartes (1596-1650) and Rationalism

Just as the skepticism of the sophists was answered with the rationalism of Plato, Descartes's rationalism was a response to the humanistic skepticism of the earlier period that, having placed man at the center of the world, he did not trust his own strength to sustain it.

Descartes did not accept the belief of the skeptical in the impossibility of knowledge, nor in the weakness of reason. He decided to systematically doubt everything until he found something that was so diaphanously true that he could not doubt it.. Descartes discovered that he could doubt the existence of God, the validity of sensations (empiricist axiom), and even the existence of his body.

Cogito ergo sum: the first and undoubted truth

He continued in this way, until he discovered that he could not doubt one thing: his own existence as a self-aware and thinking being. It cannot be doubted that it is doubted, because, in doing so, the very action that is denied is carried out. Descartes expressed his first undoubted truth with the famous: Cogito ergo sum. I think, therefore I exist.

Starting from his own existence, Descartes justified the existence of God by means of arguments that were already questioned at that time. He also established the existence of the world and the body itself, and the general accuracy of perception.

Descartes believed that a correct method of reasoning can discover and prove what is true. He advocates, as a good rationalist, for the deductive method: discover by reason the obvious truths and deduce from them the rest. This method is opposite to the inductive method proposed by Francis Bacon and adopted by the empiricists.

Descartes, however, did not rule out the usefulness of the senses, although he believed that facts have little value until they are ordered by reason.

From Philosophy to Psychology and knowledge about cognition

Descartes was not the first to justify his own existence in mental activity. Already the first rationalist, Parmenides, he had stated “Because it is the same to think and to be”, And Saint Augustine had written“ if I am mistaken, I exist ”(for Descartes, on the other hand, that he doubts all Transcendent truth, the question would have been "if I'm mistaken, I don't exist"), and just a century before, according Gomez Pereira: “I know that I know something, and who knows exists. Then I exist.”The Cartesian novelty lies in sustaining all meaning over doubt, and cementing the only certainty in logical truth.

From Descartes, philosophy will become more and more psychological, seeking to know the mind through introspection, until the emergence of psychology as an independent scientific discipline, in the nineteenth century, based on the study of consciousness through the introspective method (although only for the first generation of psychologists).

Descartes affirms the existence of two types of innate ideas: On the one hand, the main ideas, those of which there is no doubt, although they are potential ideas that require experience to be updated. But he also speaks of innate ideas regarding certain ways of thinking (what we would now call processes, without specific content, only ways of operating: for example, transitivity). This second class of innateness will be developed in the eighteenth century by Kant, with its synthetic a priori judgments.

Universal Mechanism

Descartes enriches the theory of Galileo with principles and notions of mechanics, a science that had achieved spectacular success (clocks, mechanical toys, fountains). But in addition, Descartes is the first to consider mechanistic principles as universal, applicable both inert matter and living matter, microscopic particles and bodies celestial.

The mechanistic conception of the body in Descartes is as follows: the characteristic of the body is that of being res Amplia, material substance, as opposed to res cogitans or thinking substance.

These different substances interact through the Pineal gland (the only part of the brain that does not repeat itself hemispherically), mechanically affecting each other.

The body has receptor organs and nerves or hollow tubes that internally communicate some parts with others. These tubes are traversed by a kind of filaments that at one end join with the receptors, and at the other with some pores (like lids) of the ventricles of the brain that when opened allow the "animal spirits" to pass through the nerves, which influence the muscles causing the movement. He did not distinguish, therefore, sensory and motor nerves, but he had a rudimentary idea of ​​the electrical phenomenon that underlies nervous activity.

René Descartes' legacy in other thinkers

Will be Galvani, in 1790, who, from the verification that the contact of two different metals produces contractions in the muscle of a frog, shows that electricity is capable to cause in the human body an effect similar to that of the mysterious "animal spirits", from which it could easily be deduced that the nervous impulse was of the bioelectric. Volta attributed this effect to electricity, and Galvani understood that it was generated by the contact of two metals; From the discussion between the two arose, in 1800, the discovery of the battery, which started the science of electric current.

HelmholtzIn 1850, thanks to the invention of the myograph, he measured the reaction delay of the muscle when stimulated from different lengths (26 meters per second). The mechanism of the sodium pump would not be discovered until 1940.

The importance of the pineal gland

In the pineal gland Descartes places the point of contact between the spirit (res cogitans, thinking substance) and the body, exercising a double function: control over excessive movements (passions) and, above all, conscience. Since Descartes does not distinguish between consciousness and consciousness, he deduced that animals, which did not possess soul, they were like perfect machines without psychological dimension, that is, without feelings or consciousness. Already Gomez Pereira he had denied the psychological quality of sensation in animals, reducing their movements to complicated mechanical responses of nerves operated from the brain.

The result was that a part of the soul, traditionally associated with movement, became an intelligible part of nature and, therefore, of science. Psychological behaviorism, which defines psychological behavior as movement, is indebted to Descartes' mechanism. The psyche was configured, on the other hand, solely as thought, a position that would reappear later with cognitive psychology, if it is defined as the science of thought. For Descartes, however, thought was inseparable from consciousness.

A characteristic, however, common to these approaches, as is widely the case in the rest of the modern sciences, is the radical separation between the knowing subject and the object of knowledge. Both movement and thought will become automatic, proceeding according to predetermined causal chains in time.