A question I received: Why does a liver in spirituality correspond to the state of an embryo when there are more important organs, such as the brain and the heart?
My Answer: An embryo represents the smallest desires, which are just beginning to develop. They are also called “liver.”
When these desires develop further and become bigger, they are called “the heart.” When they develop even more, they are called “the brain.”
This is always the same ten Sefirot, which become revealed in a more developed, deeper, richer, and more complex form, following the sequence: liver -> heart -> brain.
Their material branches in our world also possess the same qualities. For example, you might sever a liver, but even if a part of it remains, the liver will always be restored and grow. Doctors say that it is similar to a snake: You can cut off its tail and it will grow back. That’s because a liver corresponds to the first level, called “inanimate” or Nefesh.
You can’t do the same thing with the heart because it already corresponds to a completely different level – Ruach. This organ is already independent; while a liver, on the other hand, nullifies itself and carries out its work mechanically. In contrast, the heart works autonomously, participating on its own, and therefore it belongs to the level of Ruach.
The brain is even more advanced and belongs to the degree of Neshama (soul); it is connected to spirituality. The brain does not act by simply submitting to its nature, like the liver or the heart. Rather, it is connected to the Upper Level. In other words, it receives instructions and nourishment from spirituality, working as a receptor for spiritual information.
This is also evident from looking at the activity of the organs. The liver cleanses the blood, and blood belongs to the inanimate level. That is the liver’s function: to cleanse the body of waste, or to function as a “janitor.”
The heart already provides the whole body with the force of life and movement. That is why it’s called Ruach – the spirit of life. However, this is still not life itself, but only its spirit. Life itself comes from the soul – Neshama.