What does Aristotle’s “sleep-test ethics” look like, and how does it differ from the common test?

Aristotle's sleep-test ethics is a fundamental theory which states that people who sleep soundly after making an ethical decision, have probably made the right decision. On the other hand, it assumes that people who have made the wrong decision will likely lack sleep. It relies on personal instincts and insights when approaching an ethical decision. However, it differs from other ethical theories which define the steps one should follow when making an ethical decision. For instance, Kantian ethics states that ethical decisions are those made from a sense of duty, as opposed to expectations of rewards. Additionally, the utilitarian theory states that ethical decisions are those which benefit most people in society. The sleep-test theory therefore deviates from other ethical theories since it does not provide the criteria for making ethical decisions; it only provides a measure of assessment on whether the decision made is ethical (through the ability to sleep soundly). This presents fundamental weaknesses since external factors may affect the ability to sleep. For instance, a person who has made an ethical decision but is physically unwell, may still find it difficult to sleep. The sleep-test ethics is therefore seen by many as failing to address the critical steps that should be followed when making an ethical decision.
l

"Sleep-test ethics" refers to a concept of ethical evaluation that is based on one's personal instincts, which could also be called one's "gut feelings" or "moral compass." The idea is that if someone can (theoretically) sleep with sound conscience after taking some action, then that action must have been morally just. Of course the idea shouldn't be taken literally, as one's ability to sleep well is not a direct reflection of morality or the consequence of any one action.
The strictest interpretation of sleep-test ethics, called "me-ism," holds that morality is completely subjective to the evaluator, and thus whatever feels right for someone is morally right (to that person).
Greek philosopher Aristotle subscribed to a version of sleep-test ethics, placing value on one's innate sense of morality. Where he differed from either general or strict interpretations of the concept, though, is that he believed several variables must be controlled for the moral evaluation to be accurate/valid. The issue at hand could not be an individual compulsion. The evaluator must be of a certain level of quality, mature and thoughtful, of good character. Ultimately, he believed moral instinct was secondary (and even reactionary) to logic, common sense, and relevant facts. Further, he believed that correct moral intuition drew upon socially acceptable behavior and customs. In summary, Aristotle's sleep-test ethics were a far cry from the typical concept—a highly (and scientifically) regulated, elitist/meritocratic version of the idea.