Sir

In his Correspondence 'Replacement of animals in research will never be possible' (Nature 457, 147; 2009), Roberto Caminiti makes a case for retaining the current breadth of medical research in using non-human primates. Although immense progress has been made from scientifically well-founded work on non-human primates, I cannot agree with his contention that it will never be possible to replace these animals in research.

To my mind, there is a moral inconsistency attached to studies of higher brain function in non-human primates: namely, the stronger the evidence that non-human primates provide excellent experimental models of human cognition, the stronger the moral case against using them for invasive medical experiments. From this perspective, 'replacement' should be embraced as a future goal.

We should not assume that good medical science is by definition morally justifiable or morally acceptable. The European Union proposal that sparked Caminiti's Correspondence is rekindling this morally and scientifically essential debate.