What are the Passions of the Soul?

94. What are the movements of the blood and spirits that cause the five preceding passions

Those 5 passions are so closely connected or opposed to one another. It is easier to consider them all together rather than to treat each one separately, as was done with Admiration.

Their cause is not solely in the brain but also in the heart, spleen, liver, and all other parts of the body insofar as they serve in the production of blood and subsequently of spirits.

For even though all the veins carry the blood they contain to the heart, it sometimes happens that the blood from some veins is pushed with more force than that from others; it also happens that the openings through which it enters the heart, or those through which it exits, are more widened or narrowed at different times.

97. The main experiences that serve to understand these movements in Love

By considering the various alterations that experience shows in our body while our soul is agitated by different passions, I notice in Love, when it is alone, that is, when it is not accompanied by strong Joy, Desire, or Sadness, that the heartbeat is regular and much stronger and more forceful than usual, that a gentle warmth is felt in the chest, and that the digestion of food happens very quickly in the stomach, so that this Passion is beneficial for health.

98. In Hatred

On the contrary, in Hatred, I notice that the heartbeat is irregular, smaller, and often faster, that one feels chills mixed with a certain harsh and prickly heat in the chest, that the stomach ceases to function properly and tends to vomit and reject the food eaten, or at least to corrupt it and turn it into bad humors.

99. In Joy

In Joy, the heartbeat is regular and faster than usual, but not as strong or as large as in Love, and one feels a pleasant warmth, not only in the chest but also spreading to all external parts of the body, with blood visibly flowing there in abundance; and sometimes one loses appetite because digestion occurs less than usual.

100. In Sadness.

In Sadness, the heartbeat is weak and slow, and one feels as if there are bands around the heart that squeeze it, and ice that freezes it, communicating their coldness to the rest of the body; and yet one sometimes still has a good appetite and feels that the stomach does not fail to do its duty, provided that there is no Hatred mixed with the Sadness.

101. In Desire

Desire agitates the heart more violently than any of the other Passions and provides the brain with more spirits; which, passing from there into the muscles, make all the senses sharper and all parts of the body more mobile.

102. The movement of blood and spirits in Love

These observations, and many others would be too long to write down.

These have led me to conclude that when the intellect represents an object of Love, this thought in the brain creates the impression that directs the animal spirits through the nerves of the sixth pair to the muscles around the intestines and stomach.

This makes juice from the food, which then turns into new blood.

This blood is pushed to the heart with more force than that in other parts of the body, without stopping in the liver.

It enters the heart in greater abundance and excites a stronger heat. This is because it is coarser* than that which has already been rarefied several times by passing and repassing through the heart.

This makes it also send spirits to the brain, whose parts are larger and more agitated than usual.

These spirits strengthen the impression that the first thought of the lovable object made there, obliging the soul to dwell on this thought.

This is what constitutes the passion of Love.

103: In Hatred

On the contrary, in Hatred, the first thought of the object that gives aversion directs the animal spirits in the brain to go to:

• the muscles of the stomach and intestines to prevent the juice of the food from mixing with the blood. This is done by narrowing all the openings through which it usually flows.
• the small nerves of the spleen and the lower part of the liver, where the bile receptacle is.
  • This is so that the blood usually rejected to these places come out and flow with the blood in the branches of the vena cava to the heart.

This causes many inequalities in the heart’s heat. This is because:

• the blood that comes from the spleen hardly warms and rarefies
• the blood that comes from the lower part of the liver, where there is always bile, ignites and dilates very quickly.

This makes the spirits going to the brain gain:

• very unequal parts, and
• very extraordinary movements.

Hence, they:

• strengthen the ideas of Hatred already imprinted there
• dispose the soul to thoughts full of bitterness and resentment.

104. In Joy

In Joy, the nerves of the rest of the body act, and less of those of the spleen, liver, stomach, or intestines.

Particularly, the nerves around the openings of the heart. These opening and widening of these openings allows the blood that the other nerves drive from the veins to the heart to enter and exit more than usual.

The blood that then enters the heart has already passed and repassed several times, coming from the arteries to the veins, it dilates very easily and produces spirits whose parts being very equal and subtle, are suitable for forming and strengthening the brain’s impressions that give the soul cheerful and calm thoughts.

105. In Sadness

On the contrary, in Sadness, the openings of the heart are very narrowed by the small nerve surrounding them, and the blood in the veins is hardly agitated at all: which means that very little of it goes to the heart.

However, the passages through which the food juice flows from the stomach and intestines to the liver remain open; so that appetite does not diminish, except when Hatred, which is often joined with Sadness, closes them.