What adjective descibes a 'stooge' in a Socratic dialogue?

Suppose one constructs a dialogue in which a second participant is clearly there just to provide ballast while the first participant (the author) promotes a point of view. You could refer to the second as a stooge, a prop etc. But I'm looking for an adjective, and "the stoogy guy" doesn't sound all that learned. (-:

A better noun than 'stooge' might lead to a good adjective, but all I really need is the adjective.

Solution 1:

I don't know of any single word representing the role you're describing... But depending whether the role of the "stooge" is adversarial or complementary, I do think an idiom might be appropriate:

Straw man: a weak or imaginary argument or opponent that is set up to be easily defeated (M-W)

OR

Straight man: a member of a comedy team who says things that allow a partner to make jokes (M-W)

Update: I can't provide the links, but "Socratic straw man" returned about 90k Google results while "Socratic straight man" returned about 60k.