These days, I usually prefer to resist reducing several distinctions down to one “really true” one that covers them all.
But this is one case where it is warranted.
Over the last two years, and especially the last year, I have gravitated more and more away from a nominalist position towards a realist one. However, there is a tendency among realists to draw a line between reasoning and rational evaluation on the one hand, and persuasion on the other.
Alasdair MacIntyre was someone who made this argument throughout his corpus. More recently, I have read Edward Feser espousing a similar point of view; nominalists have to hope their “side” “wins out” whereas moral realists can actually stake out positions equivalent to how scientists stake out positions.
There seems to be a fair amount of wishful thinking about the nature of rational evaluation going on (though far be it from me to critique Feser, an authority on philosophy of mind, on this subject).
But it seems to me that reasoning just is persuasion, judgement just is rhetoric.
If reasoning is taking evidence and arguments from sources we trust and attempting to arrive at a judgment, then it is first an foremost attempting to discover what conclusion we find persuasive. Even if we decided that the evidence is inconclusive, this is a judgment we have been persuaded of.
To believe some version of metaphysical and moral realism is not the same thing as believing, as Karl Popper framed the epistemology of the Enlightenment, that truth is manifest. Yet it seems to me that reducing persuasion to mere manipulation, as MacIntyre for example does, leaves one with either the belief that truth is manifest, or a fairly strong version of epistemological skepticism.
You can be unethical in your attempts to win people to your point of view, of course. You can be deliberately misleading, for example. But that doesn’t make persuasion unethical per se, any more than the existence of false advertising indicts advertising as a practice, or the existence of murderers indicts humanity in general.
In a healthy unity of politics, ethics, and rhetoric, we seek to persuade while being open to being persuaded; we hold a high standard of evidence for persuading ourselves before going out to attempt to persuade others.
But there is no reasoning, no rational evaluation, no dialectic, that is distinct from persuasion.