The term speciesism was first introduced into
formal language by R. Ryder in his work
Victims of Science: The Use of Animals in Research. It refers to the disproportionate moral weight give to one species, namely
humans. He compares speciesism to racism. He puts it thus:
"Racists of European descent typically have not accepted that pain matters as much when felt by Africans, for example, as when felt by Europeans. Similarily, those who I would call 'speciesists' give greater weight to the interests of members of their own species when there is a clash between their interests and the interests of another species."
A defence of speciesism
It can be argued that as we are human beings, it is perfectly natural for us to favour our own species - after all, selfishness is part of our survival instinct. This isn't to say that we should treat animals with no ethical concerns at all, because doing so diminishes us as moral agents.
Instead, we should continue treating animals with base respect, but recognize and admit that we see a human as more important than an animal. Animal testing is justifiable by proportionate means - so long as there is a positive enough outcome for animal testing - such as saving a life - it is morally acceptable.