Natural Philosophy #7 Isaac Newton’s Eyeball

“Hero” might seem to be the wrong word to use when one looks at dictionary definitions of the word, but Isaac Newton is someone whose work I admire greatly, whose career was wider and more interesting than most people know, a scholar who revolutionised science, a man of such single minded dedication that he stuck a bodkin in his eyeball as part of an experiment, a transformer of the Royal Mint, and ….. a man who I have a “family tree” connection to relative to my own education and career as a scientist.

I wrote those words as an introduction to a post on this blog about 4 years back and told the story of how Dr C and I were connected to Isaac scientifically. I also highlighted a series of books about or including him, both factual and in a trilogy of novels. Do visit that post, (Standing on the Shoulders of Isaac Newton). I am certain that at least one of the books will interest you, there is only one that is science related.

Today I want to tell you about the weirdest, most bizarre, eye watering experiment that Isaac performed on himself. He was the observer AND the subject, at least his eyeball was! Isaac Newton wrote two mega manuscripts, “Opticks” and “The Principia”, the former being about light and it’s properties. Many of his early experiments as a young man involved him “messing about” with prisms, especially one in which he used multiple prisms to refract a narrow beam of light shining through a pinhole in his window blind. As expected, the white light hitting the first prism was split into the full range of spectrum colours, but the second prism although bending the light again did NO further splitting. Evidence that white light is made up of a series of other colours that can NOT be split further.

Continuing his fascination with light, Isaac was curious about why some people, but not all, saw strange coloured spots in front of their eyes, and spots of differing colours. Clever chap that he was, this gave him the notion that the eyeball was also acting as a sort of prism or lens that determined (from one person to another) what the brain behind the eyeball perceived (via ganglion cells etc). He realised that he would never be able to work out the cause or mechanism of this effect while light passed through his own eyeball unhindered. So he decided to do something about it! I think you can tell what happens next!

Isaac used a bodkin, a blunt ended needle, which he put in his eye between the eyeball and outer socket bone. And ……. wiggled it around! He saw these dark and coloured spots seen by others during wiggling but not while the bodkin was stationary, all duly reported in his notebook.

This effect is due to the creation of what we now call phosphenes, which is the phenomenon of seeing light without light actually entering the eye. So essentially it is a neurological effect caused by stimulating the eyeball which sends signals to the visual cortex producing what we see in our “minds eye” I suppose. Isaac Newton didn’t make any Earth shattering discovery from his experiment, nor did he create a particular hypothesis surrounding it. But it is certainly a striking example of how these new scientists of the age were determined to discover how the world worked, and the extent to which they would go to derive provable facts and generalised theories. Speculation, religious and cult indoctrination was coming to an end as The Enlightenment dawned. From now on, everything had to be presented, discussed, replicated and evidenced! Does that maxim continue today? (The Cancellation of Science)

Categories: Natural Philosophy, Philosophy

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8 replies

  1. sticking a needle in your eye is a true sign of commitment…

    Liked by 1 person

  2. Fantastic! Almost motivational. I want to be committed to anything as Newton was to science.

    Liked by 1 person

  3. I think I read most of just one of those novels. Far from sure. Whatever it was, I read it in early 2005 .. It was amazingly weird ..
    He is definitely someone to make a hero out of, so you’re not on the wrong track. 😀


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