The process of deduction follows standards of logic but the question I have right off the bat is "What do we mean by rational?".

What does a "universal definition for rational deduction" have to do with virtue ethics?

Matching leads.

Something that encompases a epistomlogical view point, not merely a formula of organisation and expanding on hypotheses based on prescriptivist views.

I can't quite remember where but there's the problem of universals. You might find that useful. The name suggests a link.

Virtue sought
to know the ought
Vice shed
peace when dead
there are rules
rigid fools
never say never
always whenever
one nor two
will ever do
all together
is bad weather

Masturbation is healthy :smile:

Isn't that just equivalent to "an absolute objective way to know something"? Then the problem is subjectivity/objectivity, which no one can agree on because most of us agree that the world is external but all experience is internal. So there is no one shoe fits all answer.