Perhaps you're referring to "qualia"? Supposedly, it's an open question in philosophy. I'm no expert myself, but I figured I'd mention it in case you found the

Perhaps you're referring to "qualia"? Supposedly, it's an open question in philosophy. I'm no expert myself, but I figured I'd mention it in case you found the subject worth pursuing. http://plato.stanford.edu/entries/qualia/ http://plato.stanford.edu/entries/qualia/ http://en.wikipedia.org/wiki/Qualia http://en.wikipedia.org/wiki/Qualia Obligatory xkcd: http://xkcd.com/32/ http://xkcd.com/32/