I think it isn't precise to say that they value different things, since the deontologist doesn't decide in terms of values. Speaking of values is practical from the point of view of a consequentialist, who compares different possible states (or histories) of the world; values are then functions defined over the set of world states which the decider tries to maximise. A pure ideal deontologist doesn't do that; his moral decisions are local (i.e. they take into account only the deontologist's own action and perhaps its immediate context) and binary (i.e. the considered action is either approved or not, it isn't compared to other possible actions). If more actions are approved the deontologist may use whatever algorithm to choose between them, but this choice is outside the domain of deontologist ethics.
Deontologist rules can't force one to act as if one valued some total amount of murders (low or high), as the total amount of murders isn't one's own action. Formulating the preference as a "deontological" rule of "you shouldn't do things that would lead you to believe that the total amount of murders would increase" is sneaking consequentialism into deontology.
Formulating the preference as a "deontological" rule of "you shouldn't do things that would lead you to believe that the total amount of murders would increase" is sneaking consequentialism into deontology.
This is not at all clear to me. The Kantian Categorical Imperative is usually seen as a deontological rule, even though it's really a formulation of 'reflective' concerns (viz., 'you should not act as you would not have everyone act', akin to the Silver and Golden Rule) that could be seen as meta-ethical in their own right.
I think there’s a confusion in our discussions of deontology and consequentialism. I’m writing this post to try to clear up that confusion. First let me say that this post is not about any territorial facts. The issue here is how we use the philosophical terms of art ‘consequentialism’ and ‘deontology’.
The confusion is often stated thusly: “deontological theories are full of injunctions like ‘do not kill’, but they generally provide no (or no interesting) explanations for these injunctions.” There is of course an equivalently confused, though much less common, complaint about consequentialism.
This is confused because the term ‘deontology’ in philosophical jargon picks out a normative ethical theory, while the question ‘how do we know that it is wrong to kill?’ is not a normative but a meta-ethical question. Similarly, consequentialism contains in itself no explanation for why pleasure or utility are morally good, or why consequences should matter to morality at all. Nor does consequentialism/deontology make any claims about how we know moral facts (if there are any). That is also a meta-ethical question.
Some consequentialists and deontologists are also moral realists. Some are not. Some believe in divine commands, some are hedonists. Consequentialists and deontologists in practice always also subscribe to some meta-ethical theory which purports to explain the value of consequences or the source of injunctions. But consequentialism and deontology as such do not. In order to avoid strawmaning either the consequentialist or the deontologist, it’s important to either discuss the comprehensive views of particular ethicists, or to carefully leave aside meta-ethical issues.
This Stanford Encyclopedia of Philosophy article provides a helpful overview of the issues in the consequentialist-deontologist debate, and is careful to distinguish between ethical and meta-ethical concerns.
SEP article on Deontology