Consequentialism or Teleologic ethics is the philosophical view that the moral value of an act is to be judged on its consequences, rather than the act itself. Consequentialism is therefore opposed to deontological ethics. The most well known school of consequentialism is utilitarianism. Consequentialism is a broad term, encompassing many schools of thought and one is advised to familiarise oneself with each school to fully understand what consequentialism is.
All moral reasons for acts are provided by facts that the acts are necessary enablers for preventing harm or promoting good.
The requirement of ethics to consider the interests of all creatures and not merely one's own is good reason for treating utilitarianism as presumptively the best ethical theory.
Actions are transient things, soon gone forever. Hence, one might think, in the long run only the results remain, so the only thing that really matters about an action is its results.
Rationality and objectivity are impartial; they do not favor one person over another. Hence to be moral is to care about people equally or impartially, so far as one can, which means trying to benefit people as much as one can.
According to consequentialism, just as there is nothing special about me when it comes to the effects of my action, so there is nothing special about me and my duty when it comes to the duty to perform the action.
You are normally morally permitted to favor yourself over strangers and often morally required to favor strangers over your children, which conflicts with common sense (however, this argument seems to ignore ethical egoism).
If the greatest total can be created only by exploiting the miserable to make the happy even happier, then such consequentialism would seem to say that you should do it. In the real world, however, this is seldom possible without the use of false dilemma.
The relative importance of ignorance. It can be difficult to for someone applying consequentialist ethics to forsee what the consequences they seek to uphold are. Indeed many philosophical systems hold that it impossible to know with absolute certainty any consequences of any choices. Is it ethical to flip a coin that saves a life if it comes up heads, and costs a life if it comes up tails?