Does the Torah Mention the Brain? Jewish Wisdom on Mind, Body, and Soul

Shir asks: “Hello. In my academic studies, the lecturer of one of my courses said that he is not aware of any mention of the brain in the Torah. I decided to look into this matter, since all the wisdom of the world is found within our Torah. Is there any proof for this? The lecturer also said that if I bring evidence, he will present it in his course, so this is also an opportunity for Kiddush Hashem (sanctifying God’s name). Thank you very much.”

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Shalom and blessings Shir,

Judaism has always viewed the human body as a vessel that serves the soul, because the true source of our awareness and thought lies in the soul. The body is merely the tool that gives expression to the intelligent will of the soul, just as a car transports the driver inside it.

In this sense, all the organs of the body, despite their immense complexity, are only a sophisticated machine in the hands of the true “driver,” the soul. The brain itself does not “think” thoughts; rather, the soul within the brain uses it as a tool to express its desires, just as the driver uses a car as a tool to get from place to place.

The soul fills the entire body. As our Sages said (Berachot 10a): “Just as the Holy One, blessed be He, fills the whole world, so the soul fills the whole body.”

Nevertheless, it does seem clear that the main “machine” of the body is indeed the brain, through which the soul governs the body. We can find hints of this both in Scripture and in the words of the Sages, who recognized the brain as the tool the soul uses to express thought and speech in this world.

Scriptural and Talmudic Hints

The first hint lies in the commandment of tefillin (phylacteries): the hand tefillin are placed opposite the strength of our body and the heart that pumps blood to all the limbs, while the head tefillin are placed opposite the brain, the source of intellect and thought. The head tefillin testify to the importance that the Torah assigns to the intellectual source in the head. Interestingly, the head tefillin contain four compartments, just as the frontal brain has four divisions.

The Torah also frequently uses the term “rosh” (head) as the directing and governing force over the body or over the people:

• “And the Lord said to Moses: Take all the heads of the people” (Numbers 25:4).

• “You are the head of the tribes of Israel, and the Lord has anointed you to be king over Israel” (I Samuel 16:17).

The use of “head” and “first” emphasizes its role as leader and controller over all.

The Talmud also contains expressions that show the brain as the source of intellect and thought. For example, in Menachot 80b, an expression used toward an absurd argument is: “It seems he has no brain in his skull.” A similar phrase appears in Yevamot 12a. This indicates that the brain was recognized as the seat of wisdom, and that someone lacking it was considered foolish.

Other rabbinic writings use phrases like “not out of lightheadedness” (Pesachim 10), again linking the head with the source of judgment and reason.

By contrast, references in the Bible to the “heart” are generally figurative, poetic expressions, as in: “He told her all his heart” (Judges 16:17). The heart pumps blood to the whole body, including the brain, so it is rightly considered the life-source of the body, and thus serves as a metaphor for the soul that gives life to the body. This is the reason that the heart holds such symbolic importance in biblical language.

The Rambam’s Explicit Teaching

The first explicit discussion of the brain appears in the writings of the Rambam (Maimonides), who was also a great physician. While earlier sages did not find it necessary to describe the brain’s function (since they focused on the soul as the true governing force), Rambam wrote clearly that the brain commands all the organs.

In Guide for the Perplexed (Part III, Chapter 32, paraphrased into simple Hebrew), he explains: “When you contemplate the natural works of God, His wisdom and kindness will become clear in the way He created living beings, combining their organs and connections step by step. A striking example is the way movement is achieved. The front part of the brain is very soft, while the back part is harder. The spinal cord is harder still, and becomes progressively harder as it extends. The nerves are the instruments of sense and movement. Therefore, the nerves that control the most delicate senses, like the eyelid and the cheek, arise from the brain. The nerves needed for the movement of the large organs arise from the spinal cord. The fine nerve that originates in the brain is too soft to move an organ by itself, so God designed the body such that the nerve connects to a fiber, which connects to a muscle. The nerve is strengthened by ligaments and becomes a tendon, which attaches to a bone. In this way the nerve gradually acquires the strength to move the organ. I gave you this example because the wisdom of the Creator is revealed in the usefulness of the organs, and all of it is calculated, evident, and understandable to anyone who contemplates it with reason and intelligence.”

The Rambam described, already 800 years ago, the wonders of creation through the way the brain commands all the body’s organs. These words are not only medically insightful but also deeply inspiring, testifying to the harmony between Torah wisdom and the natural sciences.