Sir

Your Editorial “PhD — club or history?” (Nature 429, 789; 200410.1038/429789b), about the withdrawal of Jan Hendrik Schön's doctorate, raises an important point. You argue that a PhD is a “piece of history” and that by revoking Schön's, as a sanction against fabricating results, the University of Konstanz is treating a PhD as a mere “club membership”.

However, a PhD is seen by the wider scientific community as a de facto ‘licence’ to perform science. It is true that some notable scientists, including the late John Maynard Smith (see Nature 429, 258–59; 2004), have not needed the benefit of a PhD to carry out excellent science. But holders of the degree are perceived by the general public as being experts in their fields. I would argue that knowingly publishing fraudulent results does far more to diminish the status of a PhD than selling the bogus doctorates widely available on the Internet “for only US$35 plus postage”.

Although Schön's PhD thesis was found to be free of malpractice, no one would argue that someone passing a driving test flawlessly could not, at some later date, have their licence revoked should their conduct behind the wheel suggest they are no longer a safe and responsible driver. Given the trust that the scientific and non-scientific communities place in a PhD, it is not unreasonable to withdraw one under certain circumstances — rare though I hope these would be.