A fine May evening and Millie, our dog leaps at the suggestion of a walk. The warmth means the walk will be longer than usual and the spring air is filled with scents. Nearing the hospital, there was a scuffle between three men in blue shirts and a large strongly-built man they were seeking to detain. Two women in hospital uniform came running on to the scene; then a Garda car came up the road. The dog walked on with an air of indifference.

Walking back through the cathedral close, we came to the stop of Saint Canice’s step. No less than three cats were to be seen, two on a window sill and one beneath a car. Generally fearful of cats, particular Calcifer, the sexton’s cat that patrols the cathedral grounds. Millie seems to summon up her courage and gives a hard stare to the three felines who are completely unmoved by the canine presence. Seemingly feeling her honour was satisfied, Millie turned and continued the walk back to the deanery. Lying contentedly on the study floor, does she recount the encounter with satisfaction? Does she tell herself that, single-handedly, she faced down a whole herd of cats? What is it that dogs dream about as they sleep beside the chairs of humans?

Perhaps canine dreams are not so different from those of their human counterparts. A Belfast man once told me of an acquaintance who had boasted at telling an intimidating neighbour exactly what he thought of him. “Aye,” said the Belfast man, “when did you tell him that?”

“When he was half a mile down the road,” said the acquaintance.

Perhaps idle boasting is not such a silly attitude. Playing and replaying mental videos of the incidents of a day has been the cause of countless lost hours of lost sleep. One can tell oneself that it is pointless to constantly rake over the ashes of the past, but that does nothing to relieve the stress felt.

Revisionism is not the exclusive preserve of politicians or historians. Being able to perceive the past, even to rewrite a few of the lines, can be a useful if, while not falsifying the facts, it can help one adjust to those facts. Anyway, everyone perceives things in their own way, objective accounts are rare; what one person recalls as a negative experience might be entirely differently recalled by another person. Personal revisionism might relieve the stress that causes sleeplessness.

If, Dolittle-like, it were possible to ask Millie about her indifference to the arrest and her thoughts on the cats, one wonders what she might say.