The massive review of infant death convictions following in the wake of the successful appeal of Angela Cannings opens up much more than the question of so-called Munchausen’s syndrome by proxy. It has thrown suspicion on the whole concept of expert knowledge.

Evidence from the child health specialist Sir Roy Meadow was a key factor in this case and yet it is now seen more as prejudice than reliable knowledge. Who, then, should we believe? Sir Roy had introduced the Munchausen diagnosis in 1977 and had become the expert on his own creation, giving evidence at countless trials. Things began to go wrong when he claimed at the Sally Clark trial that the chances of losing two infants to cot death were 73 million to one. He would later admit that there was little basis for this statistic. Soon, other “experts” were coming up with their own figures, ranging from 8,500 to one to even 100 to one. But just how useful are statistics here? The chances of winning the National Lottery are much slimmer than this each week, yet someone usually gets lucky. Could an expert be brought in to deny a winning Lotto card, citing the statistical improbability of anyone actually winning? Statistics are helpful in many fields but not when it comes to the detailed investigation of the life story of a human being. And this, of course, is what matters when the life of someone suspected of infanticide is being explored. Even when statistics are not invoked, human behaviour is often judged in relation to norms which have been statistically defined and sold as expert knowledge.

Society has fetishised the idea of expert knowledge to such an extent that it has become a commodity. Often a piece of research lies neglected, since its pursuit will not pay financial dividends. Knowledge thus becomes fragmented; focused, for example, on specific parts of the body. Despite the need for specialisation, this should not detract from a comprehensive view of the patient.

Specialisation often leads to a lack of communication whichcan have life-changing consequences. For example, from time to time a child is born with indeterminate gender. In a study of these “intersexed” infants, Suzanne Kessler has shown a disparity between the expert opinion of urologists and paediatric endocrinologists. If some form of external male genitalia exists, the urologist will privilege penis size over the condition of having one X and one Y chromosome to determine if the infant is male. Kessler says that urologists tend to want to make ambiguous cases male, while paediatric endocrinologists are more likely to suggest that the child be raised as female.

Now, assuming that the parents of such infants are not medical experts, who should they believe? And it might also be asked whether this is only a matter of medical expertise. Should a philosopher be brought in to add to the discussion? But who decides which one? Will it be the one who has published the most, or the one with a knighthood? Another recent study said we are more likely to believe what well-known people tell us. Astonishingly, this research was funded, published and then reported in the press. This fact is testimony to the need we have to legitimise knowledge — even when it is obvious. The less value we give to the internal process of learning, the more we expect knowledge to be provided to us from the outside.

Darian Leader is a psychoanalyst and author