What does consequentialist ethics (Folgenethik) claim, and where is it more attractive than duty ethics?
That an action — or a rule for acting — is evaluated by its consequences; which makes it more humane and flexible than rigid duty ethics, at the price of needing to predict the future and agree on what counts as good.
The core claim is simple: the moral evaluation of an action or of a rule of action depends on its consequences, and on nothing else. Consequences are where the moral facts are.
This licenses things duty ethics forbids outright: on a consequentialist view it is permissible to lie and even to kill if undesirable, still worse consequences cannot be averted any other way. Compared with duty ethics, this looks more humane and more flexible — it does not require you to tell the truth to the murderer at the door, and it does not treat a rule as more important than the person the rule was meant to protect.
Two structural problems come with the package, and they are not details:
- Lack of predictability. Good and bad consequences have to be foreseen in order to be weighed, and we are poor at that. Since the theory grounds moral evaluation in something that is not yet known at the moment of acting, an action can be judged right and turn out catastrophic.
- The need for a shared conception of the good. Weighing consequences requires an agreed standard of what counts as a good outcome. In a pluralistic society there is no such standard lying around, and a consequentialist calculation performed with a contested notion of "good" reproduces the disagreement rather than resolving it.
Tip: Consequentialism converts a moral question into a prediction problem plus a valuation problem. That is its strength — both are tractable — and its weakness: it is only as good as the prediction and the valuation.
Go deeper:
Stanford Encyclopedia: Consequentialism — every variant and every escape route the theory has developed against the standard objections.
Crash Course Philosophy: Utilitarianism — Bentham and Mill in ten minutes, with the »it licenses terrible things« problem posed sharply.- Wikipedia: Consequentialism — the family tree — act versus rule, negative, two-level, motive consequentialism.