I can see how to convert a Consequentialist system into a series of Deontological rules with exceptions
In the case of consequentialists that satisfy the VNM axioms (the only interesting kind) they need only one Deontological rule, "Maximise this utility function!".
However, not all Deontological systems can be converted to Consequentialist systems. Deontological systems usually contain Absolute Moral Wrongs which are not to be done no matter what, even if they will lead to even more Absolute Moral Wrongs.
I suggest that they can. With the caveat that the meaning attributed to the behaviours and motivations will be different, even thought the behaviour decreed by the ethics is identical. It is also worth repeating with emphasis the disclaimer:
This isn't to say such a conversion is always easy and it does rely on reflecting off an epistemic model but it can be done.
The requirement for the epistemic model is particularly critical to the process of constructing the emulation in that direction. It becomes relatively easy (to conceive, not to do) if you use an evaluation system that is compatible with infinitesimals. If infinitesimals are prohibited (I don't see why someone would prohibit that aspect of mathematics) then it becomes somewhat harder to create a perfect emulation.
Of course the above applies when assuming those VNM axioms once again. Throw those away and emulating the deontological system reverts to being utterly trivial. The easiest translation from deontological rules to a vnm-free consequentialst system would be a simple enumeration and ranking of possible permutations. The output consequences ranking system would be inefficient and "NP-enormous" but the proof-of-concept translation algorithm would be simple. Extreme optimisations are almost certainly possible.
1- Which is by definition not deontological.
2- A fairly common deontological rule is "Don't murder an innocent, no matter how great the benefit." Take the following scenario:
-A has the choice to kill 1 innocent to stop B killing 2 innocents, when B's own motive is to prevent the death of 4 innocents. B has no idea about A, for simplicity's sake.
Your conversion would have "Killing innocents intentionally" as an evil, and thus A would be obliged to kill the innocent.
My apologies if this doesn't deserve a Discussion post, but if this hasn't been addresed anywhere than it's clearly an important issue.
There have been many defences of consequentialism against deontology, including quite a few on this site. What I haven't seen, however, is any demonstration of how deontology is incompatible with the ideas in Elizier's Metaethics sequence- as far as I can tell, a deontologist could agree with just about everything in the Sequences.
Said deontologist would argue that, to the extent a human universial morality can exist through generalised moral instincts, said instincts tend to be deontological (as supported through scientific studies- a study of the trolley dilemna v.s the 'fat man' variant showed that people would divert the trolley but not push the fat man). This would be their argument against the consequentialist, who they could accuse of wanting a consequentialist system and ignoring the moral instincts at the basis of their own speculations.
I'm not completely sure about this, but figure it an important enough misunderstanding if I indeed misunderstood to deserve clearing up.