Since recently familiarising myself with evolutionary psychology literature, I have been amazed by how frequently scathing criticism is thrown at authors by way of the words ‘biological reductionism’. In a series of letters in the Journal, Rose & Lucas (Reference Rose and Lucas2001) criticise Abed (Reference Abed2001) for, sure enough, using the words “if it is not ‘biologically deterministic’ to claim that…”. This made me chuckle, as Rose declared himself to be a neuroscientist. I fully accept the importance of understanding the neurophysiology of the brain. However, among the amazing revelations of recent years I now know that serotonin is involved in depression, obsessive—compulsive disorder, anxiety disorders, aggression, schizophrenia and goodness knows how many other psychological disorders, yet we proudly tell our patients with depression that their illness involves a problem with serotonin. To complicate matters further we now have to tell them that there are countless different versions of serotonin.

‘Biological reductionism’ occurs in all spheres of biology. It is time that this reality was accepted and ceased to be used for devaluing the arguments of those who profess what some others may deem politically incorrect theories. I make a special plea to journal editors, as the frequency of this retort is such that free (and potentially legitimate) speech is at times being compromised.