Today is Ascension Day. There is an ancient tradition on this day called the beating of the bounds. Going back at least to Alfred the Great, the clergy and people of the local parish church would process around their boundaries, setting the geography to mind and mentally fixing notable landmarks. In a world before maps and title deeds, clarity about boundaries was passed down through memory. Young people would take sticks and bash out various important intersections, shouting “mark, mark, mark”. Sometimes, as a way of helping them commit places to memory, the youngsters would be whipped at various key junctions. Their cries would then be bought off with money.

In some parishes they still continue to beat the bounds. In the parish of St Mary the Virgin, Oxford, they collectively perambulate through some otherwise private bits of the university colleges, even through a college kitchen, so as to reassert the ancient boundary. At All Hallows by the Tower, in the City of London, they recreate a riot that took place in 1698 between the parish and the Tower over what bit of land belonged to whom.

I cannot help but think there is something Brexit-like about this ancient tradition – that globalisation was washing away so many of our familiar boundaries, and that many of us felt exposed and vulnerable without them. It was almost as if we needed to reassert a sense of place, to mark our connection to the land on which we live.

We had a hustings for the general election in my church on Sunday night. Apart from the terrifying Ukip candidate, none of the others had a bad word to say about globalisation. Even the Greens, the original anti-globalisation party, have shifted their emphasis, now talking about the need to muster international heft in order to tackle the worldwide challenge of climate change. It disappoints me that they have exchanged their wellies for suits. Their connection with the land, and sympathy with a simpler, slower rhythm of life, was the best thing they had going for them. Whatever happened to small is beautiful?

The evolutionary psychologist Robin Dunbar has famously argued that the human brain is not capable of maintaining more than about 150 stable relationships at any one time. This is the optimal number of people who can live in a community together based on trust and moral obligation. Dunbar first calculated this number by plotting brain size against group size against grooming time in monkeys. But looking through historical parish records, it turns out that 150 is also the average English village size in the 18th century. And 150 is the average village size in the Domesday Book.

The parish, it seems, is the perfect size for a successful moral community. And that’s why the beating of the bounds had a hidden moral purpose. For historically, one of the practical purposes of clarity about parish boundaries was that they determined who was responsible for looking after whom. For well over 200 years, between the dissolution of the monasteries and the Industrial Revolution, successive poor laws made the local parish responsible for its destitute members. The community was obliged to look after its own. It was the parish that organised the building of almshouses and the raising of local taxes to support the poor. This system survived until the great reforms of 1832, after which the poor had to go into a workhouse to find support. With industrialisation, and the globalisation that followed in its wake, the link between the relief of poverty and the local community was broken.

Look up the word parochial in the dictionary. First it will probably say that the meaning of parochial derives from the ecclesiastical parish, which is true. Then it may offer a number of unflattering synonyms: narrow-minded, provincial, insular, blinkered, illiberal, intolerant etc. These are just the sorts of epithets that remainers use for leavers.

Yet if Dunbar is correct, parochial is precisely the optimal size for maintaining strong moral commitments and what the military call “unit cohesion”. Cosmopolitans may disparage the small-mindedness of leavers. But scientists tell us our brain size has actually been fairly constant for about a quarter of a million years. At the size it is, parochial is the perfect scale for our moral flourishing. I suspect that support for Brexit was partly motivated by the fear that we were outrunning older, deeper versions of social solidarity. Politicians should mark, mark, mark.