Query: by what objective criteria do we determine whether a political decision is rational?

I propose that the key elements -- necessary but not sufficient -- are (where "you" refers collectively to everyone involved in the decisionmaking process):

• you must use only documented reasoning processes:
  • use the best known process(es) for a given class of problem
  • state clearly which particular process(es) you use
  • document any new processes you use
• you must make every reasonable effort to verify that:
  • your inputs are reasonably accurate, and
  • there are no other reasoning processes which might be better suited to this class of problem, and
  • there are no significant flaws in in your application of the reasoning processes you are using, and
  • there are no significant inputs you are ignoring

If an argument satisfies all of these requirements, it is at least provisionally rational. If it fails any one of them, then it's not rational and needs to be corrected or discarded.

This is not a circular definition (defining "rationality" by referring to "reasonable" things, where "reasonable" depends on people being "rational"); it is more like a recursive algorithm, where large ambiguous problems are split up into smaller and smaller sub-problems until we get to a size where the ambiguity is negligible.

This is not one great moral principle; it is more like a self-modifying working process (subject to rational criticism and therefore improvable over time -- optimization by successive approximation). It is an attempt to apply the processes of science (or at least the same reasoning which arrived at those processes) to political discourse.

So... can we agree on this?

This is a hugely, vastly, mindbogglingly trimmed-down version of what I originally posted. All comments prior to 2010-08-26 20:52 (EDT) refer to that version, which I have reposted here for comparison purposes and for the morbidly curious. (It got voted down to negative 6. Twice.)