04/03/2026
Anyways, Isaac Newton poked his eye for an experiment. In 1666, a young Isaac Newton was obsessed with understanding the nature of light and color. To test whether vision was caused by external light or internal pressure on the nerves, he decided to use his own eye as a laboratory.
The “Bodkin” Experiment
Newton took a bodkin—a long, blunt sewing needle or a small probe used for leather—and slid it between his eyeball and the bone of his eye socket. In his own journals, he described the process with unsettling detail:
“I tooke a bodkine gh & put it betwixt my eye & [the] bone as neare to [the] backside of my eye as I could: & pressing my eye [with the] end of it... there appeared severall white darke & coloured circles.”
Why did he do it?
Pressure Phosphenes: He wanted to see if physical pressure could trigger the same visual sensations as light. By pressing on the back of his eye, he successfully produced “phosphenes”—those colorful spots you see when you rub your eyes too hard.
The Nature of Light: This helped him realize that the brain interprets signals from the optic nerve as “light,” regardless of whether those signals were caused by actual light waves or physical pressure.
He didn’t stop there...
Newton was notoriously reckless with his eyes. In another experiment, he stared at the sun with one eye for as long as he could stand it to study “after-images.” He ended up having to shut himself in a dark room for several days to recover his sight, and he claimed it took months before his vision fully returned to normal.
The takeaway: Newton’s genius was matched only by his willingness to risk his own health for data. It’s a miracle he didn’t end up blind before he could finish Principia.
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