Final answer:
Ethical egoism is a normative theory suggesting one ought to act in their own self-interest. It is often supported by arguments from rational egoism but criticized for its implications on social welfare and conflicts of interest. Psychological egoism, conversely, suggests all actions are motivated by self-interest.
Step-by-step explanation:
Ethical egoism is a normative ethical theory that prescribes individuals to act in their own self-interest. This philosophy comes in two main variants: strong ethical egoism, which asserts that it is always morally right to pursue one's own greatest good, and weak ethical egoism, which states that it is always right to pursue one's own greatest good, but not necessarily wrong to do otherwise.
Psychological egoism, on the other hand, is a descriptive theory suggesting that all human actions are motivated by self-interest, even when they appear altruistic. The argument for ethical egoism often aligns with rational egoism, which posits that it is rational to act in one's self-interest, leading to the conclusion that if acting in self-interest is reasonable, then it must be morally required.
Objections to ethical egoism generally involve criticisms of its practicality and ethical consistency, noting that not all self-interested actions lead to positive outcomes for everyone, and that self-interest could potentially conflict with the well-being of others. Additionally, the objection to psychological egoism suggests it is not necessarily true that all human action is motivated by self-interest, as people can act against their own desires or best interest.