That is all to do with the social self – the bit that is determined by the fact of being a member of a group rather than being solitary; when it comes to the family, how much more vivid is the impression that one’s fate is formed by the actions of others. Each one of us is a palimpsest on which our parents have written, and beneath their writing is the writing of their parents. Thus is family pathology transmitted, and although behavioural geneticists may argue among themselves how genes determine behaviour, the rest of us have no difficulty in seeing familiar traits being passed on from parent to child to grandchild.

This explains, but may not comfort. A child unhappy today because his father is incapable of showing him affection may not know that his father was similarly deprived by his own father, and, even if he did, would be unlikely to be consoled by such knowledge. To be doing no more than to repeat the past is rarely viewed as an excuse, least of all in the eyes of children.

And even if complete freedom of will is illusory, there are still crucial decisions we make that we might not have made and that reverberate down the years. In the case of Dr St Clair, such a decision had been made by his grandfather, who, reaching for one book in the library, had inadvertently taken another and found himself accidentally immersed in an account of life on a farm in Victoria in the late nineteenth century. That St Clair was a final-year medical student at the time, the son of a bank manager from Dumfries, and on impulse had decided to write off for information on medical careers in Australia. It was a cold, raw day in February, a month when anybody might be tempted to seek warmth and sunlight elsewhere; that undoubtedly affected his decision. Had it been a fine spring day, then the prospect of working in Aberdeen, which would otherwise have happened, might not have been so unattractive; but it was not, and the letter was written. Information came back, together with an invitation to apply for a post, and that letter determined the shape of several lives, including that of his grandson, Bertie’s psychotherapist.