In the 1600s, the brain was a mystery box with no scans, neurons, or hormones. Just gray matter and guesses. Into that fog stepped René Descartes, the 17th-century French philosopher, armed with logic and nerve.

Descartes believed the mind and body were separate things. One thought. And the other one extended in space. He called them res cogitans and res extensa. That split raised a problem he could not ignore. If the soul is not physical, how does it move a physical body? His answer was the pineal gland. It sat near the brain’s center. It was small and single.

Most brain parts came in pairs. The pineal gland did not. To Descartes, that mattered. A unified mind needed a unified meeting point.

He argued that sensory signals had to merge somewhere before becoming a single thought. Two eyes but one image. Two ears but one sound. The pineal gland looked like the only place where that could happen.

The French philosopher also believed it could move slightly. That motion, he said, guided animal spirits through the nerves. These spirits were not mystical beings. They were imagined fluids that carried signals. For his time, this was daring. He tried to connect anatomy, physics, and philosophy into one system. Most thinkers kept those worlds apart. Descartes refused to.

The Theory Failed, But It Still Matters

FrontStory / Earlier thinkers had noticed the pineal gland, but they gave it dull jobs. Galen thought it supported blood vessels.

Medieval scholars mixed it up with brain worms and vapor flows. None of it held up.

By the Renaissance, anatomists like Andreas Vesalius began cutting through myths. They showed the gland did not control mental vapors. Descartes knew this work. Still, he got key details wrong. He placed the pineal gland inside the brain cavities. It is not. He thought it could move freely. It cannot. These were fatal errors once anatomy improved.

Philosophers also pushed back. Princess Elisabeth of Bohemia asked a sharp question. How does a non-physical soul push a physical object at all? No gland could solve that.

This criticism exposed the deeper issue. The mind-body problem did not disappear. It simply changed shape. Science later dropped the soul from anatomy, but the puzzle of consciousness remained. Descartes was wrong about the gland, but right about the location. Consciousness does rely on deep brain regions. Damage them, and awareness fades. Keep them intact, and thought survives.

Modern neuroscience points to structures near the pineal gland as essential for wakefulness. The brainstem and midbrain regulate alertness. Without them, the cortex stays dark. The pineal gland itself does something else. It releases melatonin.

Why the Pineal Gland Refuses to Fade Away?

Robin / Unsplash / Even after science moved on, the pineal gland kept its mystique. It shrank in textbooks but grew in culture. Today, it lives a second life online and in wellness circles.

Many call it the “third eye.” This idea sounds ancient, but it is modern. No solid evidence ties the pineal gland to Egyptian or Hindu practice. The link formed in the twentieth century, not in temples.

The third eye story stuck because it feels intuitive. A small hidden organ. A role in sleep and dreams. A spot near the brain’s center. It invites symbolism.

Psychedelic research added fuel. In the 1990s, psychiatrist Rick Strassman studied DMT. He proposed that the pineal gland might release it during birth, death, or mystical states. DMT can produce intense visions and a sense of leaving the body. Strassman suggested this could explain near-death experiences. The idea spread fast.

However, science has not confirmed it. No strong evidence shows the pineal gland produces DMT in meaningful amounts. Still, the theory lives on in books, podcasts, and forums.