What colour is that?

Be sure to gaze at the amazing checkershadow illusion. Go now, then come back here.

A cursory check with a little computer program I have (Digital Color Meter in /Applications/Utilities/ for those of you with MacOS X) verifies that the two squares which look so different are, in fact, the same 42% grey. But the surely don't look the same. The explanation is helpful.


I’m Greg Restall, and this is my personal website. I am the Shelby Cullom Davis Professor of Philosophy at the University of St Andrews, and the Director of the Arché Philosophical Research Centre for Logic, Language, Metaphysics and Epistemology I like thinking about – and helping other people think about – logic and philosophy and the many different ways they can inform each other.


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