Retro Science - what once was science may be no longer; here is a list of outdated science notions many of which have been thoroughly debunked yet stubbornly refuse to go the way of the Dodo. My personal favorites are the concept of human equating homo sapiens, and the thorny issue of defining consciousness within scientific terms.
On the topic of nonhuman animal personhood: the fact that claims to ‘animal rights’ carry no sense of reciprocal obligations on the part of the animals towards humans raises question about the activists’ sincerity in appealing to ‘rights’ at all. However, if the activists are sincere, then they should also call for a proactive policy of what the science fiction writer David Brin has termed ‘uplift’, whereby we prioritise research designed to enable cognitively privileged creatures, regardless of material origin, to achieve capacities that enable them to function as peers in what may be regarded as an ‘expanded circle of humanity’.
One might object that the Hard Problem of consciousness (so dubbed by philosopher David Chalmers in his 1996 book, The Conscious Mind) isn’t a scientific idea at all, and hence isn’t an eligible candidate for this year’s question, but since the philosophers who have adopted the term have also persuaded quite a few cognitive scientists that their best scientific work addresses only the “easy” problems of consciousness, this idea qualifies as scientific: it constrains scientific thinking, distorting scientists’ imaginations as they attempt to formulate genuinely scientific theories of consciousness.
So at what point does a scientific conjecture which has entered into public knowledge become obsolete? Read the full list (with many more interesting examples) over at IO9.