If that’s what you’re using “the regress” to mean, sure, sign me up. But this has even less bearing than usual on whether uncertainty can be represented by probability, unless you are making the (unlikely and terrible) argument that nothing can be represented by anything.
Are you aware that Yudkowsky doesn’t dispute the regress? He has an article on it.
http://lesswrong.com/lw/s0/where_recursive_justification_hits_bottom/
If that’s what you’re using “the regress” to mean, sure, sign me up. But this has even less bearing than usual on whether uncertainty can be represented by probability, unless you are making the (unlikely and terrible) argument that nothing can be represented by anything.