How Many Makes a Viable Community?

THis is a big subject, and I’m realising the foolishness of trying to write a blog post about it, but here’s my initial thoughts anyway.
I and my partner have just returned from a stay at Monkton Wyld in Dorset, a sustainable community. I was really interested in the discussions about community we had while we were staying there, and it gave us much food for thought during the journey home. I particularly wondered what happens to people when they’re ill, or whether people with long term conditions such as ME (chronic fatigue – a few of my friends are afflicted by it) could ever have a place in such a community. At Monkton Wyld there are currently only about 12 resident members, plus short-term volunteers. It would have to be much bigger to accommodate the weak or less physically able, and also to provide outlets for the more specialised forms of human activity, like some skilled crafts such as musical instrument making for instance.
There was an interesting series of programmes on R4 about the history of friendships; apparently the maximum number of meaningful connections a person can have on average is about 100 (it might have been 150, can’t quite remember). Apparently until the industrial revolution that was the average size of the English village. Within a community of this size, certain occupations would be widely called for, others less so. One would need lots of people involved in food production, fewer involved in more skilled tasks (perhaps fruit tree training, or certain sorts of plant propagation) and very few – the musical instrument makers, scientists, thinkers etc. In fact, thinking historically, there have always been some rarefied or highly specialised areas of human activity which have needed a larger population base to make them viable. Musical instrument makers have always been based in larger communities, for example, or been itinerant, perhaps, if their trade allowed – the same principle applies. In modern communities, we need scientists and thinkers, and surely one of the benefits of a larger community is that some people can be freed up to do these less every day tasks, but ones which are have long term benefit.
An impromptu musical evening was initiated by one of the volunteers at Monkton Wyld; she had a considerable talent on the the piano and I contributed a song, teaching the chorus to the others. We had a motley collection of instruments and created an enjoyable evening, but I was left wondering where someone like myself would fit in to a community of that sort. I can garden and could probably learn to cook, but I’m not up to lots of heavy work and my particular skills lie outside the every day and the practical. I felt though that the forming of social ties was greatly enhanced by the evening, and that perhaps this is the true significance of music.