Overview
Short Answer
Ancient Israelites certainly knew brains existed—they butchered animals, treated head wounds and Jacob and Joseph were mummified in Egypt (Gen 50:2–3 and 26). But they didn't understand the brain's function. Like most ancient cultures, they attributed thought, emotion, and will to the heart and kidneys because that's where they felt these things happen.
Media & Maps
When Anatomy Meets Experience
Here's what strikes me as fascinating: the ancient Hebrews weren't ignorant of brains—they just didn't think brains did anything important. This wasn't stupidity; it was perfectly logical based on what they could observe.
Think about it from their perspective. You feel anxiety as a knot in your stomach. Fear makes your heart race. Deep emotion creates that aching sensation in your chest. When you're terrified, you might quite literally feel like your kidneys are quivering. (The Hebrew writers certainly described it that way.) But when's the last time you felt yourself thinking with your brain? You experience thought as happening in your head, sure, but you don't feel your neurons firing.
The Israelites regularly butchered animals for food and sacrifice. They saw brains. They dealt with head injuries—the skull breaks, the grey matter spills out, sometimes people die, sometimes they don't. But they never observed brain activity producing visible results the way they could watch a heart pump blood or kidneys filter urine. The brain just sat there, grey and inert, seemingly doing nothing.
So when biblical writers talk about the inner life of a person, they locate it where they experienced it: in the viscera.
The Hebrew Vocabulary of Inner Life
The Hebrew word lev (H3820) means "heart," but it's the seat of intellect, will, and emotion. When Proverbs 23:7 says "as he thinks in his heart, so is he," that's not poetic license—that's precise anatomical psychology as they understood it. The heart thinks. Plans. Decides.
The kidneys—kelayot (H3629)—represent the deepest, most hidden parts of a person's inner life. When Psalm 26:2 asks God to "test my heart and my kidneys," it's asking for examination of both conscious thought and those deep, barely conscious motivations and emotions. God "searches hearts and kidneys" in Jeremiah 17:10 because He examines both what you know about yourself and what you don't.
The intestines—the "bowels"—were the seat of compassion and mercy. That's why older translations have Jesus moved with "bowels of compassion." Our modern "gut feeling" isn't far off.
Did They Ever Look Inside Skulls?
Absolutely. Archaeological evidence shows that ancient peoples, including those in the Near East, performed trepanation—drilling or scraping holes in skulls, sometimes to relieve pressure from head injuries. Some patients survived, as evidenced by bone healing around the holes.
The Israelites would have encountered Egyptian mummification practices as well, which involved removing the brain through the nose with hooks. The Egyptians threw the brain away, by the way, while carefully preserving other organs in canopic jars. Even the Egyptians, with their advanced medical knowledge, didn't think the brain mattered much.
Military physicians (and there were such people) dealt with head wounds. They saw brain tissue. They learned that certain head injuries killed people and others didn't, but they never connected brain tissue to mental function in the way we do now.
What We Can Learn From This
Here's where this gets theologically interesting: the biblical writers' "inaccurate" anatomy doesn't invalidate their theological insight. When Psalm 139:23 asks God to "search my heart and know my anxious thoughts," the physiology is wrong but the theology is exactly right. God does examine our inner life at levels we can't fully access ourselves.
The Bible isn't a medical textbook, and God didn't correct ancient anatomical understanding because that wasn't the point. The inspired writers used the best anatomical language available to communicate profound truths about human nature, divine examination, and moral responsibility. Those truths remain valid regardless of whether thought happens in your cardiac muscle or your prefrontal cortex.
What's actually remarkable is how accurately Scripture describes human experience even while using pre-scientific anatomy. The "heart" being deceitful above all things (Jeremiah 17:9)? Neuroscience now confirms we're spectacular at self-deception. The deep places God examines? We now know about subconscious processes that drive behavior without our awareness.
The biblical writers were wrong about which organ did the thinking, but they were absolutely right about what needed examining.
Biblical Evidence & Key Passages
- Proverbs 4:23 - "Guard your heart above all else, for everything you do flows from it." The heart as the command center of moral and intellectual life.
- Psalm 7:9 - "You who test the hearts and kidneys, O righteous God." God's examination reaches both conscious and unconscious levels.
- Jeremiah 11:20 - "You test the heart and kidneys." Repeated emphasis on these organs as seats of inner life.
- 1 Kings 3:9 - Solomon asks for "an understanding heart to judge your people." Intelligence located in cardiac tissue.
- Philippians 1:8 - Paul longs for the Philippians "with the bowels of Jesus Christ" (KJV). Compassion centered in the intestines.
Practical Application
This reminds us that biblical inspiration doesn't require scientific omniscience from the human authors. God communicated through people embedded in their time, using their categories and understanding, to reveal timeless truth about Himself and humanity.
When you read about hearts and kidneys in Scripture, don't get distracted by the outdated physiology. Ask instead: What is this text revealing about human nature? About God's knowledge of us? About moral responsibility?
And here's something wonderfully humbling: our own "advanced" scientific understanding will look primitive to people in another millennium. But the theological truths Scripture teaches—about human sinfulness, divine grace, the need for redemption—those don't expire with our anatomy textbooks.
h3 id="dig-deeper">Dig DeeperRelated Reading:
- Heart (lev) in Hebrew thought - The command center of intellect, emotion, and will in biblical anthropology
- Ancient Near Eastern medicine - Medical knowledge and practice in the biblical world
- Biblical anthropology - How Scripture understands human nature and the body-soul relationship
- Progressive revelation - How God revealed truth through culturally embedded human authors
External Resources:
- The IVP Bible Background Commentary: Old Testament by John H. Walton, Victor H. Matthews, and Mark W. Chavalas
- Ancient Near Eastern Thought and the Old Testament by John H. Walton
- The Lost World of Scripture by John H. Walton and D. Brent Sandy
- Britannica - Comprehensive overview of ancient medical practices
Did you Know?
GENERAL
Ancient Egyptians removed and discarded the brain during mummification but carefully preserved the liver, lungs, stomach, and intestines in canopic jars. They believed these organs were necessary for the afterlife. The brain? Just useless grey stuffing taking up skull space. Even advanced ancient medical practitioners shared the biblical world's low estimation of brain function.
יָבֵשׁ חָצִיר — Word of our Elohim stands forever
