379. It is generally recognized that there is a vital warmth in humans and in all animals, but people do not know where it comes from. People discuss it on the basis of conjecture, so if they do not know anything about the way matter is responsive to spirit, they identify the warmth of the sun as its source, some focusing on the activity of particles and some on life itself. However, since these last do not know what life is, they are just substituting one word for another.

However, once people realize that there is a relationship of responsiveness between love and its feelings on the one hand and the heart and its derivative vessels on the other, they can know that love is the source of our vital warmth. Love radiates as warmth from the spiritual sun where the Lord is and is felt as warmth by angels. This spiritual warmth, which essentially is love, is what flows into the heart and its blood by correspondence and instills both its warmth and its life. We know that we are warmed and virtually kindled by our love, depending on its intensity, and that we become sluggish and cold as that intensity decreases. We feel and see this, feeling it in a warmth throughout our bodies and seeing it as our faces flush. In contrast, we feel its loss as a physical chill and see it as faces turn pale.

Since love is our life, the heart is the beginning and ending of our life; and since love is our life and the soul brings its life through the body in the blood, the blood is called the soul in the Word (see Genesis 9:4 and Leviticus 17:14). I will be explaining later [383] what "soul" means in its various senses.

378, 3. Volition corresponds to the heart. As I mentioned above [375], this cannot be shown in a clearer and more precise way than by examining the effects of volition. It can be shown in some detail by the fact that all the feelings that arise from love induce changes in the motions of the heart. We can tell this from the arterial pulse that acts synchronously with the heart. It has countless changes and motions in response to feelings that arise from love. The only ones we can detect with the finger are that it may beat slower or faster, boldly or gently, soft or hard, regularly or irregularly, and so on. So it varies from happiness to sorrow, from peace of mind to rage, from courage to fearfulness, from fevers to chills, and so on.

Since the motions of the heart (called systole and diastole) do vary in this way depending on the feelings that arise from someone's love, many of the ancients and some moderns have ascribed feelings to the heart and named it as the home of the feelings. So in common language we have come to speak of a magnanimous heart or a timid one, a happy or a sorrowful heart, a soft or a hard heart, a great or a mean heart, a whole or a broken heart, a heart of flesh or one of stone, of being heavy, soft, or gentle at heart, of putting our heart into a task, of giving our whole heart, giving a new heart, resting at heart, taking to heart, of not laying something to heart, of hardening the heart, of being a friend at heart. We have the words concord and discord and envy and many others that have to do with love and its feelings.

The Word says similar things because it was composed in correspondences. It makes no difference whether you say love or volition, since volition is the vessel of love, as already noted [358-361].