Thesis
• A priori definition
'1 a statement or theory that is put forward as a premise to be maintained or proved [...] 2 a long essay or dissertation involving personal research, written as part of a university degree.' Concise Oxford English Dictionary
Students tend to refer to their writing as the 'thesis'. But the 'thesis' proper i.e. the 'statement or theory' may (also) be elsewhere, depending on what model of relations between art and writing one adopts - see Practice-inclusive research.
Michael Craig-Martin An Oak Tree 1973
But then again, not, if 'The art object does not embody a form of knowledge'; if the artwork is not the medium for knowledge as a 'statement or theory'.
'Thesis', as the OED points out, is also '(in Hegelian philosophy) a proposition forming the first stage in the process of dialectical reasoning. Compare with ANTITHESIS, SYNTHESIS.'
Is there a way in which 'art' might be taken as an 'anti-thesis'?
• A posteriori definition
Macleod & Holdridge propose that 'PhD submissions themselves' offer the best way of resolving questions regarding research regulations, procedures etc. That is to say: the field is best defined by its students' work: the theses of 'submissions'. 'Practice-based research: a new culture in Doctoral Fine Art practice' Katy Macleod & Lin Holdridge; accessed 29.09.08
PhD thesis:
The artist as a multifarious agent: an artist's theory of the origin of meaning
journal papers, book articles, edited books, editorial roles, and conference papers