The Seat of Passions is Not in the Heart

33. The Seat of Passions is Not in the Heart

People think that the soul receives its passions in the heart.

In reality, the passions cause some alteration to be felt there.

This alteration is felt in the heart only through the mediation of a small nerve that descends from the brain to the heart.

This is similar to how:

• pain is felt in the foot through the mediation of the nerves of the foot,
• stars are perceived in the sky through the mediation of their light and the optic nerves.

Therefore, it is no more necessary for our soul to exercise its functions immediately in the heart to feel its passions than it is for it to be in the sky to see the stars.

34. How the Soul and the Body Act on Each Other

The soul has its principal seat in the pineal gland from where it radiates to the rest of the body through the mediation of the spirits, nerves, and even the blood, which, participating in the impressions of the spirits, can carry them through the arteries to all the members.

The small fibers of our nerves are so distributed in all the parts of the body.

Various movements are excited in them by sensory objects, opening variously the pores of the brain.

This causes the animal spirits contained in its cavities to enter into the muscles, moving the limbs various ways.

Other causes can variously move the spirits and guide them into various muscles.

The pineal gland is so suspended between the cavities containing these spirits that it can be moved by them in as many different ways as there are sensitive diversities in objects.

But it can also be variously moved by the soul, which is of such a nature that it receives as many different impressions in it, that is, it has as many different perceptions as there are different movements in this gland.

Similarly, reciprocally, the body’s machine is so composed that from the sole fact that this gland is variously moved by the soul, or by any other cause whatsoever, it pushes the spirits surrounding it toward the pores of the brain, which guide them through the nerves into the muscles, thereby making them move the limbs.

35. Example of How the Impressions of Objects Unite in the Pineal Gland

If we see an animal coming towards us, the light reflected from its body paints two images, one in each of our eyes.

These two images form two others, through the mediation of the optic nerves, on the inner surface of the brain facing its cavities.

From there, through the mediation of the spirits that fill these cavities, these images radiate in such a way toward the pineal gland surrounded by these spirits that the movement composing each point of one of the images tends toward the same point of the gland, toward which the movement forming the point of the other image representing the same part of this animal also tends.

Thus, the two images in the brain become one on the gland, which acts immediately on the soul to make it see the shape of the animal.

36. Example of How Passions are Excited in the Soul

If this shape is very frightening and has a lot in common with things that have previously been harmful to the body, it excites fear in the soul.

This will then excite either courage or dread according to:

• the body’s temperament
• the soul’s strength
• whether one has previously defended oneself or fled from harmful things related to the present impression.

This makes the brain so disposed in some men that

The spirits reflected from the image formed on the gland go from there:

• partly into the nerves that turn the back and move the legs to flee
• partly into the nerves that enlarge or constrict the orifices of the heart
  • This agitates the other parts that receive the blood, making it rarefied in a different way than usual.
  • This blood sends spirits to the brain, which are suitable to maintain and strengthen fear, that is to say, which are suitable for keeping open, or reopening, the pores of the brain that guide them into the same nerves.

For from the sole fact that these spirits enter these pores, they excite a particular movement in this gland, which is established by nature to make the soul feel this passion.

These pores relate primarily to the small nerves that serve to tighten or enlarge the orifices of the heart, this makes the soul feel it primarily as in the heart.