In my limited experience, UCMA supporters explicitly rejected the assertion that "arguments" and "being convinced by an argument" are equivalent to "evidence" and "performing a bayesian update on evidence". So those three would be enough for evidence and updates, but not enough for argument and persuasion according to my next-best-guess of what they mean by "argument" and "convinced".

For one, you need some kind of input system, and some process that looks at this input and connects it to pieces of an internal model, which requires and internal model and some structure that sends signals from the input to the process, and some structure where the process has modification access to other parts of the mind (to form the connections and perform the edits) in some way.

Then you need something that represents beliefs, and some weighing or filtering system where the elements of the input are judged (compared to other nodes in the current beliefs) and then evaluated using a bunch of built-in or learned rules (which implies having some rules of logic built-in to the structure of the mind, or the ability to learn such rules, both of which are non-trivial complexity-wise), and then those evaluations organized in a way where it can be concluded whether the argument is sound or not, and the previous judgments of the elements integrated so that it can be concluded whether the premises are also good, and then the mind also requires this result to send a signal to some dynamic process in the brain that modus ponens the whole thing into using the links to the concepts and beliefs to update and edit them to the new values prescribed by the compelling argument.

Whew, that's a lot of stuff that we need to design into our mind that seems completely unnecessary for a mind to have sentience, as far as I can tell. I sure hope we don't live in the kind of weird universes where sentience necessarily implies or requires all of the above!

Which is where the Occam/SI comes in. All of the above is weird, very specific, and extremely complex in most machine designs I can think of. Sentience is itself complex, but doesn't seem to require the above as far as we can tell. Positing that minds also require all these additional complexities seems like a very bad idea. Statistically, 'A' is always more likely than 'A and B'. Positing UCMA is a bit akin to positing 'A and B and C and Fk but not Re and not any of Ke through Kz and L1..273 except L22'.