I rarely write about the practical aspects of writing a PhD thesis on this blog. Last weekend, I was one of the examiners on two different doctoral thesis juries at the Université de Paris X. The candidates - both were successful, by the way, and both received 'félicitations du jury', which is the best you can get - are students of Professor Alain Pellet.
During the defenses, which are public in France, Professor Pellet spoke about a feature of doctoral theses that contributes to a problem of excessive length. This is a more serious problem in France, where theses are often well over 500 pages, than it is in Ireland and the UK, where we have a rather strict rule that keeps them well under 300 pages. He said that students have a tendency to include too much 'scaffolding', meaning that they frame the thesis with lengthy developments about background issues that are not really necessary. Often this involves showing the examiners that they have learned their lessons well, and that they are comfortable with general concepts and ideas in the discipline. It is a way to cite the major writers in the field., including often those with a philosophical perspective.
He said - and we all agreed - that this is to be avoided. For example, in a thesis on some feature of the International Criminal Court, it is not necessary to provide the entire background of international justice, the rationale for prosecution, and so on. If you are writing about an aspect of international human rights law, there is no need to remind us of the details of the adoption of the Universal Declaration of Human Rights (unless, of course, this is really germane to the topic).
In other words, don't surround your thesis with too much 'scaffolding'. Get to the point quickly.