Is Consciousness…Animal spirits?
A brief history of the beginnings of consciousness, part I.
In order to get a sense of what consciousness is, we need to start by looking at its history. And throughout history, the concept of consciousness has undergone quite a few changes. In fact, with the risk of oversimplifying it, we could say that the concept of consciousness has enjoyed a period of beginning, a middle, and it has a “now”.
But while we briefly outline the major chain of events in this history, I’d also like to suggest two rules of thumb for WHEN in history the concept of consciousness evolved, which can be used by anyone to point out these moments on their own. As we shall see, these rules of thumb are just as telling as the history itself.
The first widely popular, modern use of the term “consciousness” came during the scientific revolution from René Descartes (1596–1650 CE), who proclaimed that “By the term thinking I understand everything that it is in us so that we are immediately conscious of it. Thus all the operations of the will, intellect, imagination, and sense are thoughts“ [1]. Before this time, the meaning of the word ‘consciousness’ was not even in the same conceptual ballpark as today. In fact, “consciousness” comes from the Latin “-scio”, which means to know, and “con-”, which means together [2]. As in, “knowing together”. And up until the time of Descartes, when you would use it, you would say “conscious with someone”. As in, I was conscious with you of this blog post, which meant I “knew together with you” of this blog post.
However, the time of Descartes marks the start of the ‘middle’ portion in the history of consciousness, so before we look into that in more detail, we should start with its beginnings. And, as with anything else that has to do with Western philosophy and science, that means looking at the ancient Greek thinkers.
In ancient Greece, the qualities we commonly attribute to conscious thought were given to ‘the soul’. [3] In his work Timaeus, Plato (5th-4th century BCE) described the soul as being composed of three parts: The soul beneath the diaphragm which handled sexual longing. The soul in the thorax which handled courage and might. And the soul of the head, which dealt with intellect. This idea came from an analogy that he made between the body and the state. In The Republic, his famous earlier work, Plato proposed that a state’s members are composed of three classes: the common folk, the warriors and the philosophers. And so he divided the soul into three as well: the soul that handled basic instincts, the warrior soul of the thorax and the intellectual soul in the brain. Here, we find clues to the first rule of thumb for when exactly in history the concept of consciousness experiences an upgrade:
The concept of consciousness changes when the analogies that are available to us for understanding the body change.
In particular, when new analogies for the parts of the body that are believed to generate conscious thought come about, so does our concept of consciousness eventually experiences an upgrade. We’ll see more examples of this later, but in this case, Plato made an analogy between the state that he divided into three classes of people to divide the ‘soul’ (i.e. ancient term for consciousness) into three parts as well.
Numerous people came up with variations of Plato’s thoughts on the soul as time went on, but a major turning point in the history of consciousness came with the work of Claudius Galen (129 – 200/216 CE), a famous Greek anatomist and experimentalist that performed countless dissections in order to examine the body and reach his conclusions. In one of his experiments, he had cut the laryngeal nerve of a pig and noticed that the pig has stopped squealing, which hinted that the voice, a primary instrument of the ‘soul’, came from the brain — an early nod to the modern view of consciousness arising from the brain. During his work with the brain, Galen noticed something that we scarcely consider: The living brain moves in a rhythmic fashion, like the heart. Here is a video that shows the brain in action (don’t view it if you are faint of heart):
Of course, we know today that this is because the heart pumps blood throughout the body, including the brain, however Galen came to a different conclusion: That the brain’s movements were due to the fact that it is also a pump, like the heart. He also noticed that there were four cavities in the brain. We now know to be our ventricles, the areas of the brain that contain cerebrospinal fluid.
This fluid functions as a shock absorber for the brain and spine, transports nutrients and removes waste. However, Galen, who didn’t have the tools we have to understand brain anatomy, concluded that the substance within these four chambers contained “animal spirits”, which were the ‘soul’s’ primary instrument for influencing the body. In Galen’s view, the brain acted like a pump to push the “animal spirits” through the veins, and these would animate the body in ways that the soul willed. His experiments showed that if the chambers of the brain were damaged but the tissue was allowed to heal, the animal would recover, so the substance in the ventricles couldn’t be the soul itself — since in that case, any damage to the ventricles would release the soul and would kill the animal instantly. Instead, the soul, Galen speculated, was to be found in the tissue of the brain. Not a bad conclusion to reach for a 2nd century philosopher! And here, we have an example of the second rule of thumb of when in history the concept of consciousness undergoes a revolution:
The concept of consciousness changes when the knowledge that we have of the human body changes.
In this case, Galen performed dissections and vivisections of animals and human cadavers to learn of the body’s anatomy and reach the conclusions that were to be built upon by other scholars for over a thousand years. The most popular variation of Galen’s ideas thought up by later intellectuals was that each cavity of the brain had a specific mental function. For example, Nemesius (390 CE) thought that the first ventricle of the brain is designed for the common senses, the second for thinking and the third for memory. The idea that each ventricle had specialized functions is now known as ventricular psychology, and it was to be an extremely influential view, repackaged and reformulated for hundreds of years by a number of famous ancient scholars, from Saint Augustine to Avicenna, to Albertus Magnus, and even Leonardo da Vinci in the 15th century.
It took the famed anatomist Vesalius (1516–1564 CE) and his influential work for the strong hold of ventricular psychology to start wearing off. Vesalius established the principle of “ocular evidence” — that is, he believed that describing the anatomy of the human body should be based on empirical observation. His work eventually came to dominate anatomy, a position that had previously belonged to Galen, who had been the gold standard for over a millennium prior. [4] Vesalius’ detailed drawings of ventricles show them to be very much like how we know them today, and described them as full of fluid.
Thanks to Vesalius and other anatomists that ascribed to the principle of “ocular evidence”, when Descartes began first using the term “consciousness” in the 17th century, ventricles were no longer center stage, although the concept of “animal spirits” were still in vogue, but we’ll tackle that in the next post.
Until then, the thing to take home is that there seem to be two major rules of thumb for when the philosophical and scientific concept of consciousness undergoes a revolution:
1). When new analogies that we can make to the human body appear — For example, Plato’s view that the body has three souls came from an analogy between the body and his new division of the state — like the state has three types of people, there are three souls.
2). When new knowledge that we have of the body appears — For example, Galen’s idea that the brain contained four chambers with “animal spirits” that transmitted the will of a soul which resided in the surrounding brain tissue came from experiments that increased his knowledge of human anatomy.
When either of these two things changed throughout history, the concept of consciousness eventually changed as well.
We’ll let these two rules be our guide as we continue the history of the concept of consciousness in the next post.
[1] Descartes, R. (1640) Rationes Dei, II, Objectiones, Definition I.
[2] Zeman, A. (2005). What in the world is consciousness?. Progress In Brain Research, 1–10. doi: 10.1016/s0079–6123(05)50001–3
[3] Smith, C. (2014). Beginnings: Ventricular Psychology. History, Philosophy And Theory Of The Life Sciences, 1–19. doi: 10.1007/978–94–017–8774–1_1 (I highly recommend this resource for anyone wanting to look at the early period in the history of consciousness)
[4] Andreas Vesalius | Anatomy in the Age of Enlightenment. Retrieved 16 April 2020, from http://www.umich.edu/~ece/student_projects/anatomy/people_pages/vesalius.html
