With G-d's help we now begin chapter 9 of Tanya. With the close of chapter 8, an entire stage in the flow of the sefer has been completed, not the whole subject, but one of its stages, and so it is worth first taking stock of the structure of the chapters we have learned until now.
A review of the flow from the beginning of Tanya until this chapter:
Chapters 1-2: Every Jew has two souls. The first soul comes from the side of kelipah and sitra achra, and its qualities were listed in a few brief lines at the end of chapter 1; the second soul in a Jew is "chelek Eloka mimaal mamash," literally a part of G-d above.
Chapters 3-5: An explanation of the nature of the nefesh haElokis. The soul has ten powers, divided into two groups: three intellectual powers, chochmah, binah and daas, and seven middos, the powers of emotion (chapter 3). It also has three levushim, garments: thought, speech and action, and it is through them that the nefesh haElokis engages in Torah study and the fulfillment of mitzvos (chapter 4). The emphasis in chapters 4-5 is that when the nefesh haElokis functions through its three garments, it rises to heights utterly beyond any comparison to the level it stood on beforehand.
Chapters 6-8: An explanation of the nature and character of the nefesh habahamis, the animal soul. It too has ten powers, three of intellect and seven of emotion, except that their order is the reverse of the G-dly soul's (as will be explained further on); and it too has three garments of thought, speech and action. When a person stumbles in forbidden thought, speech or action, the soul descends from its source in kelipas nogah and sinks into the three completely impure kelipos. In chapters 7-8 the Alter Rebbe brought examples of various punishments, such as kaf hakela and Gehinnom, in order to highlight the sheer depth of the descent that takes place at the moment of sin.
With that, the explanation of the two souls is complete: the nefesh haElokis in chapters 3-5, and the nefesh habahamis in chapters 6-8. The first part of chapter 9 opens a new topic: where in the human body each of these two souls is located, and what the dwelling place of each one is.
The dwelling place of the animal soul:
The Alter Rebbe begins: "והנה מקום משכן נפש הבהמית שמקליפת נוגה בכל איש ישראל" - "Now, the dwelling place of the animal soul that stems from kelipas nogah in every Jew." A "mishkan," a dwelling place, means the fixed and primary location, the base from which all of its activity is driven. And where is it? In the heart, and within the heart itself, in the left ventricle.
Before we go further, it is worth reflecting on the very statement that its dwelling place is the heart. As was explained at the beginning of chapter 6, one of the essential differences between the nefesh haElokis and the nefesh habahamis is that the animal soul looks in everything for itself: for the "I," for what is worthwhile, for the personal calculation of profit and loss. It does not do a thing in which it has no interest. That is why its dwelling place is the heart, for the heart is entirely emotion: it loves, it hates, it fears, it grows angry, and emotion is the very essence of animality.
You might object: after all, positive emotions also reside in the heart, including the love of G-d!
The clear difference is that a positive emotion does not arise in the heart instinctively, of its own accord. A person does not arrive at love of G-d on his own, as though it suddenly awakened by itself; rather it comes through hisbonenus, contemplation and depth of thought in the mind, and from there it seeps down into the heart. Worldly desires, by contrast, rise up on their own and require no effort at all. The animal soul dwells in the heart and goes to work immediately, without anything having to arouse it, while the G-dly soul needs to be awakened and does not come of itself.
From this emerges a practical lesson, as Rabbi Nachum Goldschmid explained in his shiurim on Tanya (collected in the sefer "Biurei HaRan"g al HaTanya"): the Alter Rebbe is not coming to teach us anatomy, but to show a person how to identify the source of whatever stirs within him. At times a person is convinced that a certain attraction has its source in kedushah, since it looks good and fine. To this comes the rule: if the thing is drawn forth by itself, without effort and without contemplation, know that its source is the animal soul, for anything that rises from the heart on its own is a sign that it comes from the nefesh habahamis.
Why specifically the left ventricle:
The heart has two chambers, right and left (and each of them has an atrium and a ventricle; here the intent is the left side as a whole). The Alter Rebbe defines the left ventricle as the place that is filled with blood. Seemingly, though, the right side is also full of blood, and every limb of the body is full of blood, so what does he mean?
The answer lies in how the circulatory system works: all the organs receive their blood from the left ventricle, and it is oxygenated blood that enables the organs to function. After the body's organs consume the oxygen in the blood, the blood returns to the right side, and from there it is sent to the lungs to receive oxygen, and from the lungs it returns to the left ventricle and once again out to the organs. It emerges that although blood is physically present in the right side, it is blood without vitality and without oxygen, blood that is merely passing through; whereas the left ventricle is the center of the blood, the blood that carries vitality, and it is what dispatches it to all the organs. That is the meaning of the statement that the left ventricle is filled with blood.
The Alter Rebbe continues and brings the verse: "כי הדם הוא הנפש" - "for the blood is the soul." It is known that there is a minimum quantity of blood without which a person cannot live, and in the language of halachah (in the Gemara and in the Rambam) it is called a "revi'is dam," a quarter-log of blood. This revi'is is found in the left ventricle, and there it always remains, granting vitality to the entire system. Understandably, when the blood is present in all the organs in its full measure, a person functions better, is stronger and more active; but the indispensable minimum is that revi'is dam. It is about this that the verse says "for the blood is the soul," that very blood which sustains all of one's vitality is the expression of the animal soul.
Two verses, two purposes:
Already in chapter 1 (page 5b) the Alter Rebbe discussed the animal soul and wrote that it is clothed in the blood, except that there he cited a different verse: "for the soul of the flesh is in the blood." Why does he change here and bring the verse "for the blood is the soul"? Because each of the two chapters has a different aim and a different task:
In chapter 1: he was not coming to deal with the location of the animal soul, but with its essence, and to say that it is clothed in the blood, without getting into the details of exactly where. For that, the verse "for the soul of the flesh is in the blood" is enough: the soul is found in the blood, throughout the whole system.
In chapter 9: here he comes to speak specifically about the dwelling place, about that revi'is dam which is the base and the center. Therefore the earlier verse, which teaches only in a general way that the soul resides in the blood, does not suffice, and so he brings the verse "for the blood is the soul": that very blood which keeps a person alive is the soul.
In summary: in this section we reviewed the flow of the chapters learned until now, the two souls (1-2), the G-dly soul with its powers and garments (3-5), and the animal soul and its descent at the time of sin (6-8), and we began chapter 9, which deals with the place where the souls dwell in the body. We learned that the dwelling place of the nefesh habahamis is in the heart, the seat of emotion, and specifically in its left ventricle, which is filled with oxygenated blood and sends it out to all the organs. We became acquainted with the revi'is dam about which it says "for the blood is the soul," and we clarified the difference between this verse and the verse cited in chapter 1. We also learned the practical directive that emerges from all of the above: any arousal that rises from the heart on its own, without contemplation and without effort, has its source in the animal soul.
In the next section we will take up the continuation of chapter 9 and the dwelling place of the nefesh haElokis in the human body.