The latter theory was almost universally adopted until the middle of the sixteenth century, although there were numerous variants. He wrote that people who want to remember look upwards because this raises the worm-like particle, opens the passage, and enables the retrieval of memories from the posterior ventricle. People who want to think, on the other hand, look down because this lowers the particle, closes the passage, and protects the spirit in the middle ventricle from being disturbed by memories stored in the posterior ventricle Constantinus Africanus , p.
Figure 2. Thinking is associated with the animal spirit in the middle ventricle II , memories are stored in the posterior ventricle III. Left: people who want to remember look up because this raises the worm-like obstacle and enables the passage of memories from the posterior to the middle ventricle. Right: people who want to think look down because this depresses the worm-like obstacle and isolates the middle ventricle from the contents of the posterior ventricle.
Figure 3. The Worm-Like Obstacle. This illumination from ca. In several later medieval texts, the term pinea was applied to the worm-like obstacle, so that the view that the pineal gland regulates the flow of spirits the theory that Galen had rejected made a come-back Vincent de Beauvais , fol.
Ingenio conferentia. The authors in question seemed ignorant of the distinction that Galen had made between the pineal gland and the worm-like appendage. Figure 4. The Worm According to Mondino view from the left. Figure 5. The Worm According to Mondino view from above. In the beginning of the sixteenth century, anatomy made great progress and at least two developments took place that are important from our point of view. Second, Andreas Vesalius , book 7 rejected all ventricular localization theories and all theories according to which the choroid plexus, pineal gland or vermis of the cerebellum can regulate the flow of spirits in the ventricles of the brain.
But he was highly interested in anatomy and physiology as well. Descartes discussed the pineal gland both in his first book, the Treatise of man written before , but only published posthumously, first in an imperfect Latin translation in , and then in the original French in , in a number of letters written in —41, and in his last book, The passions of the soul In the Treatise of man , Descartes did not describe man, but a kind of conceptual models of man, namely creatures, created by God, which consist of two ingredients, a body and a soul.
Unfortunately, Descartes did not fulfill all of these promises: he discussed only the body and said almost nothing about the soul and its interaction with the body. The working of these bodies can be explained in purely mechanical terms. It is important to keep this in mind, for otherwise his account cannot be understood.
First, Descartes thought that the pineal gland is suspended in the middle of the ventricles. Figure 6. The Pineal Gland According to Descartes. But it is not, as Galen had already pointed out see above.
2. Descartes’ Views on the Pineal Gland
Secondly, Descartes thought that the pineal gland is full of animal spirits, brought to it by many small arteries which surround it. But as Galen had already pointed out, the gland is surrounded by veins rather than arteries. He thought that they inflate the ventricles just like the sails of a ship are inflated by the wind. But as we have mentioned, a century earlier Massa had already discovered that the ventricles are filled with liquid rather than an air-like substance.
Les Passions de l’âme
He explained perception as follows. The nerves are hollow tubes filled with animal spirits. They also contain certain small fibers or threads which stretch from one end to the other. These fibers connect the sense organs with certain small valves in the walls of the ventricles of the brain. When the sensory organs are stimulated, parts of them are set in motion.
These parts then begin to pull on the small fibers in the nerves, with the result that the valves with which these fibers are connected are pulled open, some of the animal spirits in the pressurized ventricles of the brain escape, and because nature abhors a vacuum a low-pressure image of the sensory stimulus appears on the surface of the pineal gland. Imagination arises in the same way as perception, except that it is not caused by external objects. The pores or gaps lying between the tiny fibers of the substance of the brain may become wider as a result of the flow of animal spirits through them.
Finally, Descartes presented an account of the origin of bodily movements. He thought that there are two types of bodily movement. First, there are movements which are caused by movements of the pineal gland. The role of the pineal gland is similar in all three cases: as a result of its movement, it may come close to some of the valves in the walls of the ventricles. The spirits which continuously flow from it may then push these valves open, with the result that some of the animal spirits in the pressurized ventricles can escape through these valves, flow to the muscles by means of the hollow, spirit-filled nerves, open or close certain valves in the muscles which control the tension in those muscles, and thus bring about contraction or relaxation of the muscles.
Apart from the just-mentioned type of bodily motions, caused by motions of the pineal gland, there is also a second kind, namely reflexes. The pineal gland plays no role with respect to them. Reflexes are caused by direct exchanges of animal spirits between channels within the hemispheres of the brain. They do not necessarily give rise to ideas in the sense of currents in the ventricles and are not brought about by motions of the pineal gland. The first remarks about the pineal gland which Descartes published are to be found in his Dioptrics As I have amply shown already, however, we must not think that it is by means of this resemblance that the picture causes our sensory perception of these objects—as if there were yet other eyes within our brain with which we could perceive it.
In , Descartes wrote several letters to answer a number of questions that various persons had raised. The reason I believe this is that I cannot find any part of the brain, except this, which is not double. Since we see only one thing with two eyes, and hear only one voice with two ears, and in short have never more than one thought at a time, it must necessarily be the case that the impressions which enter by the two eyes or by the two ears, and so on, unite with each other in some part of the body before being considered by the soul.
The only alternative is to say that the soul is not joined immediately to any solid part of the body, but only to the animal spirits which are in its concavities, and which enter it and leave it continually like the water of river. The pituitary gland is, though small, undivided and located in the midline, not the seat of the soul because it is outside the brain and entirely immobile 24 December , AT III, CSMK A second interesting addition to the Treatise of man that Descartes made in these letters concerns memory. The medical student Jean Cousin defended it in Paris in January Cousin and the professor of theoretical medicine Regius defended it in Utrecht in June Regius , third disputation.
The Passions may be seen as a continuation of the Treatise of man , except that the direction of approach is different. The Treatise of man starts with the body and announces that the soul will be treated later. In the Passions , Descartes starts from the other end, with man, and begins by splitting man up into a body and a soul. On the other hand, anything in us which we cannot conceive in any way as capable of belonging to a body must be attributed to our soul. Thus, because we have no conception of the body as thinking in any way at all, we have reason to believe that every kind of thought present in us belongs to the soul.
For the body is a unity which is in a sense indivisible because of the arrangement of its organs, these being so related to one another that the removal of any one of them renders the whole body defective. This is obvious from our inability to conceive of a half or a third of a soul, or of the extension which a soul occupies.
St Thomas Aquinas accepted this view and explained it by saying that the soul is completely present in each part of the body just as whiteness is, in a certain sense, completely present in each part of the surface of a blank sheet of paper. In deference to Aristotle, he added that this does not exclude that some organs the heart, for example are more important with respect to some of the faculties of the soul than others are Summa theologica , part 1, question 76, art.
Descartes and the Pineal Gland (Stanford Encyclopedia of Philosophy)
The principle of life may well held to be completely present in each living part of the body just as biologists nowadays say that the complete genome is present in each living cell. However, Descartes did not regard the soul as the principle of life. He regarded it as the principle of thought. This makes one wonder what he may have meant by his remark. What would a principle of thought be doing in the bones and toes? One might think that Descartes meant that, although the pineal gland is the only organ to which the soul is immediately joined, the soul is nevertheless indirectly joined to the rest of the body by means of the threads and spirits in the nerves.
Moreover, it is clear that not all parts of the body are innervated. He added that he thought that our ideas about gravity are derived from our conception of the soul. But it can also be moved in various different ways by the soul, whose nature is such that it receives as many different impressions—that is, it has as many different perceptions as there occur different movements in this gland. These traces consist simply in the fact that the pores of the brain through which the spirits previously made their way owing to the presence of this object have thereby become more apt than the others to be opened in the same way when the spirits again flow towards them.
However, there are some new ingredients which have no parallel in the Treatise of man. In later times, it was often objected that incorporeal volitions cannot move the corporeal pineal gland because this would violate the law of the conservation of energy. Descartes did not have this problem because he did not know this law. One would like to know a little more about the nature of the soul and its relationship with the body, but Descartes never proposed a final theory about these issues.
From passages such as the ones we have just quoted one might infer that he was an interactionist who thought that there are causal interactions between events in the body and events in the soul, but this is by no means the only interpretation that has been put forward.
In the secondary literature, one finds at least the following interpretations. There seem to be only two well-known theories from the history of the philosophy of mind that have not been attributed to him, namely behaviorism and functionalism. But even here one could make a case. According to Kneale , p. According to Putnam , Nussbaum and Wilkes , it was similar to contemporary functionalism. By transitivity, one might conclude that Descartes was either a sort of behavorist or a functionalist.
In his later years, Descartes was well aware that he had not successfully finished the project that he had begun in the Treatise of man and had not been able to formulate one comprehensive mind-body theory. He sometimes expressed irritation when others reminded him of this. On other occasions, he came close to admitting defeat.
We will follow this wise advice. He argued that we know next to nothing about the brain. Camper seems to have been the very last one to uphold the Cartesian thesis that the pineal gland is the seat of the soul, although one may wonder whether he was completely serious. Some of the reasons that Descartes gave for his view that the pineal gland is the principal seat of the soul died out more slowly than this view itself. This view was, however, refuted by Zinn in a series of split-brain experiments on dogs.
Lamettrie and many others explicitly rejected the thesis that the unity of experience requires a corresponding unity of the seat of the soul Lamettrie , ch. In scientific studies of the pineal gland, little progress was made until the second half of the nineteenth century. Towards the end of the nineteenth century, however, the situation started to change Zrenner First, several scientists independently launched the hypothesis that the pineal gland is a phylogenic relic, a vestige of a dorsal third eye.
A modified form of this theory is still accepted today. Second, scientists began to surmise that the pineal gland is an endocrine organ. This hypothesis was fully established in the twentieth century. The hormone secreted by the pineal gland, melatonin, was first isolated in Melatonin is secreted in a circadian rhythm, which is interesting in view of the hypothesis that the pineal gland is a vestigial third eye. The history of pineal gland research in the twentieth century has received some attention from philosophers of science Young , McMullen , but this was only a short-lived discussion.
As philosophy reduced the pineal gland to just another part of the brain and science studied it as one endocrine gland among many, the pineal gland continued to have an exalted status in the realm of pseudo-science. This theory is still fairly well-known today. Descartes was neither the first nor the last philosopher who wrote about the pineal gland, but he attached more importance to it than any other philosopher did. Descartes tried to explain most of our mental life in terms of processes involving the pineal gland, but the details remained unclear, even in his own eyes, and his enterprise was soon abandoned for both philosophical and scientific reasons.
- Calling the One: A Leaders Guide to Mature Interviewing.
- Managing Development Resources: The Use of Country Systems in Public Financial Management.
- Les Passions de l’âme - AbeBooks - René Descartes: .
- Shop by category.
- Literary Encyclopedia | Les Passions de l'âme!
- 18 editions of this work.
Even so, the pineal gland remains intriguing in its own right and is still intensely studied today, with even a whole journal dedicated to it, the Journal of Pineal Research. Pre-Cartesian Views on the Pineal Gland 1. Post-Cartesian Development 3. Pre-Cartesian Views on the Pineal Gland The pineal gland or pineal body is a small gland in the middle of the head.
Bibliography [AT] Adam, C. In French.
The Light of the Emotions
In Greek. Bound in full contemporary overlapping vellum, flat spine. Contemporary binding. It is his most important work after the "Discourse on Method " and the only one to directly evoke the problems of moral life. The treatise includes 3 parts: -The first one analyzes the relationships between body and soul. The treatise on the passions was written in French for the Princess Palatine Madame Elizabeth, with whom Descartes had actively corresponded.
It's probably because the author has the intention to clarify the relationships between soul and body that he evokes the moral life through this treatise; we have to notify that previously Descartes had carefully refused to consider this matter. Les Trois veritez. Toggle navigation. First edition of the "Passions of the soul" by Descartes First edition of "The Passions of the soul" by Descartes preserved in its contemporary overlapping vellum.