Over at Crooked Timber, Ingrid Robeyns considers the merits and demerits of part-time employment in the academy. She's doubtful that, as a model, it can work for those who wish to balance work and non-work activities (parenting, etc.):

But my biggest doubt whether part-time work is such a splendid idea for academics who are doing research has to do with the nature of research: whether one works on a full-time contract or a part-time contract, the literature that one has to follow to keep up to date with one’s area of research remains the same. There are ‘fixed costs’ (in terms of time and effort) for each line of research that one pursues. The consequence is that a part-timer spends as much time (in absolute number of hours) on keeping up to date with the literature, implying that she has fewer hours left for actually developing new research....

I am one of those people who (normally) doesn’t go to work on Fridays (and for the next couple of months I have one extra day off so as to be able to spend more time with our baby). I do enjoy the time I can spend with the children, and the fact that this extra day off slows us down a little. But I also sometimes feel I’m cheating myself, since it seems I am doing at least as much work as many people who are working on a full-time contract (with the difference that much of my work gets done in the evenings). In the end I am just not sure whether part-time work in academia is, all things considered, a good idea for those academics who are actively and passionately pursuing research agendas.

As Ingrid said, some aspects of the academic's job -- committee work, refereeing, university service, and, yes, teaching -- can be compartmentalized in a manner similar to other jobs. There's nothing part-time about research. But this isn't the fault of the employment system -- the fault, such as it is, lies within the nature of the academic. If you love what you do, nominal time restrictions do not matter a great deal -- a fact that occasionally drives my family around the bend.

There's a parallel to blogging here, in that the overwhelming number of people who blog do so because they like it, not because of any renumeration they receive. This renders the economics of blogging -- and online publishing more generally -- a little peculiar. The economics of sectors in which workers derive significant psychic benefits from their work differ from more mundane sectors.