The wicked, deceitful human heart.

HEART hɑrt noun. Hollow muscular organ which pumps blood through the circulatory system.

2. [in popular culture] Center of a person’s thoughts and emotions; one’s mood, feeling, enthusiasm, mood, or courage.

3. [in popular Christian culture] Center of a person’s lifeforce; one’s innermost being; the true self, particularly one’s true thoughts and feelings.

4. A conventional heart shape, as found on a deck of cards.

[Hearted 'hɑrt.ɛd adjective.]

Jeremiah 17.9-10 KWL

9 “The heart is more twisted than everything.

It’s human. Who knows it?

10 I, the LORD, examine the heart and test the kidneys,

to give men according to their ways, the fruit of their deeds.”

The ancients didn’t know much about anatomy. So all the stuff we recognize are part of brain activity, the ancients believed were the function of other parts of the body. The heart, they imagined, did our thinking. The kidneys did the feeling.

Seriously. And why not? When we get excited, our hearts beat faster. When we’re sad or mournful, we feel it in the chest, and not so much the head. They saw a connection between mental activity and the heart. So they deduced it was the cardiac muscle behind our thoughts and feelings… not our thoughts and feelings behind our heart’s behavior. Yep, got it backwards.

What’d they imagine our brains did? Well, they didn’t. Seriously: The word “brain” isn’t in the bible. Y’might find it in various bible translations, but that’s because the translators know what the brain actually does, and decided to swap it for lev or kardía where appropriate. But in the scriptures, when we come across mental activity, the authors kept referring to one’s heart.

• The thoughts Ge 6.5 or imagination Ge 8.21 of one’s heart: Of one’s mind, really.
• Saying in one’s heart Ge 11.17, 24.45, Dt 9.4, 18.21 is saying to oneself, in one’s head, or at least privately.
• One’s heart failed or fainted or was discouraged Ge 42.28, 45.26, Nu 32.7, Dt 1.28 means they lost their nerve.
• One’s heart was hardened Ex 4.21, 7.13, Dt 2.30 means one’s mind is closed.
• One’s heart was stirred Ex 35.21, 36.2 is what we’d call a brainstorm.

We still do this in our culture. When we remember, we “search our hearts.” When we rethink things, we “have a change of heart.” When we make up our minds, we “determine in our hearts.” And so forth.

Medical science didn’t realize the brain’s importance till Hippocrates in the fourth century BC, and Galen of Pergamon in our second century. For the longest time, more folks were familiar with Aristotle, who claimed the brain’s job is to cool down our blood. Considering all the bible’s talk about thinking and saying with our hearts, most people up until the Renaissance assumed the heart literally did as the bible describes.

But as I’ve said before, the bible’s not a science textbook. When its authors wrote about other subjects than God, they repeated what their culture had told them. They’d always been taught so, and God saw no reason to correct them: “No, guys, you think with your brains, not your hearts.” He had bigger fish to fry. He even used their terminology: He stated he thought in his heart. Ho 11.8 He was trying to relate to humanity, and it wasn’t the occasion for a biology lesson.

So if you’re worried about the scientific inaccuracy of the scriptures, don’t. Unlike young-earth creationists, we aren’t making anti-scientific claims about human biology based on our overly-literal interpretations of the scriptures. We’re simply reading the bible so we can understand God better. To a lesser degree, we’re also trying to understand the sin-damaged human mind better, and if the bible’s authors persisted in using “heart” to mean “mind”… well, let’s adapt.