What Color is it?

In his book, Labyrinths of Reason, at one point, William Poundstone asks if you’d be able to know if the way you see colors is the opposite of how others see it, i.e., would you be able to know if “the sensation you have been trained to call “red” is what everyone else calls “green””? You can’t compare with anything to prove either way because colors are described by comparing with something else!

I was reminded of all that when I read Ed Yong’s article. Different animals can see different parts of the spectrum e.g. some snakes can see infrared light whereas mice can’t. Until Tian Xui and his colleagues in China came along:

“(The team) injected the eyes of mice with nanoparticles that were designed to stick to the light-detecting cells in the rodents’ retinas. These particles convert incoming infrared light (that the cells cannot naturally detect) into plain old green light (that they very much can).”

While this may be impressive (or horrific, depending on your point of view), Yong makes a valid criticism on a different count:

“As far as infrared vision goes, it’s a bit of a cheat. The mice aren’t seeing in infrared; they’re seeing infrared information that’s been changed into a more perceptible form.”

David Eagleman disagrees with Yong. Hasn’t science been converting invisible information to “a range we can perceive”, he argues:

“This is what microscopes and telescopes do: changing the very small or very distant into a form we can digest with our eyes. But instead of building a large piece of equipment to do the conversion, these investigators engineered a microscopic solution, directly mating technology to biology.”

Eagleman does have a point: all those telescopic images often use radiowaves to “see” stuff, and then convert it into a range of colors that we humans can see. How is that any different?

Aha, but there is a difference, counters Yang:

“Given how the particles work, it’s unlikely that users (mice) will be able to tell the difference between “infrared” and normal green.”

Which raises the question, what if our vision does something similar to what we injected into the mice? What if our vision system combines multiple ranges of “true” colors into a single color which is what we then perceive?

A lot of questions that start in philosophy become even more fascinating when you throw science into the mix…