A meta-meme which confers resistance to a wide variety of memes (and their sociotypes), without conferring meme-allergies. In its purest form, tolerance allows its host to be repeatedly exposed to rival memes, even intolerant rivals, without active infection or meme-allergic reaction. Tolerance is a central co-meme in a wide variety of schemes, particularly "liberalism", and "democracy". Without it, a scheme will often become exo-toxic and confer meme-allergies on its hosts.

Since schemes compete for finite belief-space, tolerance is not necessarily a virtue, but it has co-evolved in the ideosphere in much the same way as co-operation has evolved in biological ecosystems.