The pineal gland is an endocrine gland developed from the pineal eye of primitive vertebrates. In higher vertebrates, it is an oval body located on the back of the diencephalon.
The human pine cone is located on the top of the third ventricle, so it is also called the honey adrenal gland. One end of it is connected to the top of the third ventricle by a thin handle, and the third ventricle protrudes into the handle to form a pine cone. Fruit body crypt.
It is 5 to 8 mm long, 3 to 5 mm wide, and weighs 120 to 200 mg. It is a gray-red, bean-like oval body.
Many people do not believe that the pineal gland is the third eye of human beings and find it incredible, but research has proven that this is an undoubted fact. Biologists have long discovered that , there is an eye frame for a third eye on the skull of an ancient animal that has long been extinct.
Later, some research showed that both turtles, fish, birds, beasts, and the ancestors of humans once had a third eye.
However, with the evolution of living things, this third eye gradually moved from the outside of the skull to the inside of the brain and was hidden, becoming what we call the pineal gland.
The human eye is like the lens of a camera, which plays the role of focusing and collecting light, while the pineal gland is like the CCD or film of a camera, which plays the role of real photosensitive imaging.
The human body’s pineal gland is relatively developed in childhood, but begins to degenerate after the age of 7.
Many believe this is our biological third eye, the "seat of the soul," the "center of enlightenment."
Historically, the pineal gland was a deeply mysterious gland.
The first person to describe the pineal gland was the ancient Roman medical scientist and anatomist Galen.
He explained the origin of the pineal gland's name (similar in size and shape to the fruit of the Lycopodium) and described its function from a medical perspective.
Later, Posidonius, Maytheus and others in late antiquity proposed the theory of psychological ventricular positioning, believing that various psychological functions are located in different ventricles. The ventricle in the front of the head is responsible for imagination, and the ventricle in the middle is responsible for imagination. The ventricle of the brain produces rationality, the ventricle at the back is responsible for memory, and the pineal gland at the top of the diencephalon has since had a relationship with the soul.
After the transformation of Augustine and others in the Middle Ages, the physiological pineal gland has acquired some mysterious functions and has become a place to regulate the human mind.
Later, some people used anatomical evidence to believe that the pineal gland was the degraded "third eye" of human beings, and it was even artificially attached with religious significance.
Descartes did not just choose the pineal gland as the site of mind-body interaction because of the mystery of this gland.
In "On the Feelings of the Soul", he gave what he considered to be a logical and interesting argumentation process.
He believes that most human organs are in pairs and symmetrical, and other organs in the brain are also in pairs. For example, humans have two eyes and two ears.
But why do people have only one stable and simple thought at the same moment? What makes the two pictures we see with our eyes and the two sounds we hear with our ears synthesized? In one body? Descartes believed that there was only one possibility, and that was the pineal gland, the only unpaired part of the brain, which brought these sensations together harmoniously.
From it we can briefly see Descartes’s thoughts of mind-body sympathy to gain a deeper understanding of his answer to “how the mind is perceived”.