Of course human visual perception is a bit more complex than that but the primary mistake here is mixing up RGB and RYB. Quirks of color perception then result in referring to the resulting color as "green" when it clearly contains blue.
https://en.wikipedia.org/wiki/Blue%E2%80%93green_distinction...
But look here, and remember the book was published in 1864: https://en.wikipedia.org/wiki/Complementary_colors
Look at the color wheels of that period and earlier, especially this one: https://commons.wikimedia.org/wiki/File:Color_star-en_(terti...
And you see that red is the opposite of green. Why not cyan? I don't know. I guess cyan simply wasn't a well recognized color back then, maybe cyan was called green (a blueish green). Maybe our perception changed with the availability of modern pigments and screens.
As for the color you see when trying the illusion, it is even more interesting because it is actually an impossible color! [1] It doesn't correspond to a wavelength of light or a combination thereof, you can only perceive it through an illusion like this one. If we follow the Wikipedia article, and considering that the afterimage appears on a dark background that would be "stygian cyan". Spooky! Again, the theory was probably unknown in 1864.
Because tradition, and the pigments they used. Red, yellow, blue worked great.
This is false. The only thing it proves is that ghosts CAN BE an illusion. Failure to recognize the difference between the two is why such books haven't stopped people believing in ghosts.
This is very important to future critical thinking because this gave people evidence to back up being skeptical for future illusions that they can't immediately explain.
If there is a mistake in common knowledge, it's the belief that hallucinations/delusions happen only to mentally ill people or on drugs.
> This is false.
It's not false, that's just the headline.
The book targeted a very specific illusion that con artists would use to scam people. That did prove the ghosts being presented as real were in fact illusions.
It is false, and it's also not just the headline.
> That did prove the ghosts being presented as real were on fact illusions.
Again, this is false. It proved only that illusory facsimiles of ghosts are possible. You cannot prove that someone didn't see a ghost just because there are non-ghost mechanisms for people to think they're seeing ghosts. That's not how proving things works.
'prove' simply needs not to be taken literally in this context. You can replace it here by 'make a suggestion that'
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