Chris Hallquist’s recent post begins with a critique of my “Against Human Weakness.”  Chris:

The problem is that once you’ve committed to “do the right thing all
day, every day,” you’ve given yourself a powerful incentive to
rationalize whatever you do do as being the right thing. I find it
interesting that Bryan is a deontologist, and has pressed a version of the argument that utilitarianism is “too demanding.”

He’s correct.  Once you commit to always do the right thing, you do indeed have a powerful incentive to rationalize the morality of your choices.  But Chris misses the bigger picture.  There are three distinct margins along which people have powerful incentives to weasel out of their moral obligations.

Weaseling Margin #1: Moral principles.  The laxer your principles, the easier they are to satisfy, as Chris explains.

Weaseling Margin #2: Morally relevant facts.  Your moral principles can be incredibly strict as long as you’re willing to fudge the empirics.  Being a utilitarian is easy if you can convince yourself that your ski trips to Colorado maximize human well-being.

Weaseling Margin #3: Moral adherence.  Strict moral principles and a clear-eyed view of the facts are painless if you see little need to actually take the actions you consider morally right.

From a microeconomic standpoint, these three margins of weaseling are close substitutes.  Indeed, as long as one margin is totally flexible, the other two can safely be perfectly strict.  Puritanical rationalists like me can seek refuge in low-key deontological moral theories, as Chris suggests.  But even the most fanatical consequentialists have two escape routes of their own.  They can, as Chris suggests, plead moral weakness.  But they can just as easily combine self-righteous puritanism with corrupt social science.  The latter is, in my experience, rampant.  As I’ve explained before:

[C]onsider the policy views consequentialists held before they studied
philosophy and social science.  Then look at the views they hold after
studying these subjects.  Notice the suspiciously high correlation? 
<sarcasm>It’s almost as if people grandfather in their
pre-existing policy preferences rather than meticulously judging them
case by case against the facts.</sarcasm>

Second, consider
the very high stability of the policy views of the typical mature
consequentialist.  A real consequentialist should be constantly
fine-tuning his policy views as new evidence arrives.  After all, as
soon as the net expected benefits of your current favorite policy fall
$.01 below the net expected benefits of any alternative policy,
consequentialism requires you to purge your old favorite policy and
adopt a new one.

Finally, consider the very high certainty of the
typical mature consequentialist.  No human being has the time to
consider more than a small fraction of policy-relevant evidence.  And
even if you did have the time to review all existing evidence, you’d
still be very far from fully understanding what’s going on.  Call it a
cliche, but the real world really is extremely complex.

Chris identifies a real problem: moral weaseling is very very very bad.  But moral weaseling is hardly unique to puritans.  And holding the other two moral margins constant, puritanism helps mitigate the problem.  So why not criticize moral weaseling in all its guises, instead of apologizing for one form of moral weaseling in the strange hope that your excuses will, on net, make human behavior better?