Full Idea
Hegel seems to argue that the immediate knowledge of self (the Cartesian premise) presupposes the activity that constitutes the self, and this presupposes desire, and hence the knowledge of objects.
Gist of Idea
Hegel claims knowledge of self presupposes desire, and hence objects
Source
report of Georg W.F.Hegel (Phenomenology of Spirit [1807]) by Roger Scruton - Short History of Modern Philosophy Ch.12
Book Reference
Scruton,Roger: 'A Short History of Modern Philosophy' [ARK 1985], p.177
A Reaction
This hardly amounts to an argument, but I find it quite sympathetic as a claim. It fits comfortably with modern externalist accounts of thought. While solipsism seems a logical possibility, it hardly amounts to a coherent account of mental life.