Clark is no fan of presuppositionalism. Here are some quotes from Stephen B. Cowan (ed.), Five Views on Apologetics. (No idea what the page numbers are. It’s the kindle edition.)
On Van Til:
Although I have read some of the published writings of Cornelius Van Til, presuppositionalism’s founding father, I have always found him baffling. Either I don’t understand what he is saying, or if I do understand it, what he says seems obviously false (or to entail obvious falsehoods) or, at best, arguably true (but seldom argued for). I am puzzled by the steady stream of his followers that has poured out of Westminster Seminary.
I have listened to the tapes (which Frame commends) of the debate between Gregory Bahnsen, presuppositional apologist, and Gordon Stein, defender of atheism. Quite frankly, I found Bahnsen’s arguments precious thin and his approach wearisome – he simply repeated over and over that unbelievers have no grounds for reason and then offered the briefest defense of his view that only Christian theism provides grounds for reason. Van Til, I’m afraid, had a similar awkward tendency to prefer assertion over argument.
Unambiguous, you could say.