I would include other people's arguments as part of the evidence that's needing to be evaluated -- others' arguments come to me not as "X therefore Y" but as "D

I would include other people's arguments as part of the evidence that's needing to be evaluated -- others' arguments come to me not as "X therefore Y" but as "Dave says that X therefore Y." I still have to do my own reasoning: is Dave credible enough that I should spend time thinking about what he said? Is X true? Does Y always follow from X? In the end, I still have to trust my own reasoning, instead of taking it on faith that Dave is right. But, as you say, maybe Dave's a good source of arguments & should be consulted often -- just not as an oracle.