Deontological (rule-based) ethics are often implicitly justified by the good outcomes their rules are presumed to create. If a moral rule was known to produce the worst possible results, its proponents would likely abandon it, revealing a hidden consequentialist foundation for their beliefs.

Our moral sense was shaped by "social selection"—the process of choosing social partners. Individuals who were trustworthy, loyal, and genuinely caring were more likely to be chosen for friendships and alliances, giving their genes an advantage. This reframes guilt and social anxiety as tools for maintaining valuable relationships.

It is a profound mystery how evolution hardcodes abstract social desires (e.g., reputation) into our genome. Unlike simple sensory rewards, these require complex cognitive processing to even identify. Solving this could unlock powerful new methods for instilling robust, high-level values in AI systems.

People's diverse values and life choices can be understood through four primary "mattering strategies": transcendent (spiritual), social (communal), heroic (self-driven excellence), and competitive (zero-sum). Understanding which strategy a person uses can decode their motivations.

In variations of Stanley Milgram's obedience experiments, the presence of nonconformists, or "principled deviants," dramatically reduced the group's willingness to inflict harm. These outsiders model ethical behavior, reining in the cruelty of others and guiding the group toward a better moral outcome.

Under the theory of emotivism, many heated moral debates are not about conflicting fundamental values but rather disagreements over facts. For instance, in a gun control debate, both sides may share the value of 'boo innocent people dying' but disagree on the factual question of which policies will best achieve that outcome.

Philosopher Rebecca Goldstein distinguishes our need for connectedness (external validation) from our "mattering instinct," an internal drive to prove our lives have value to ourselves. Confusing these two distinct needs leads to misunderstanding human behavior.

Thought experiments like the 'River of Drowning Children' suggest strict altruism requires sacrificing your entire life. However, most plausible ethical theories reject this maximal demandingness. They acknowledge that your own well-being, family, and personal projects also hold moral weight and should not be entirely sacrificed.

Expert philosophers disagree sharply on fundamental moral theories. Rather than trying to pick the 'correct' one with high confidence, a more robust approach is to acknowledge this uncertainty and aggregate across different worldviews when making high-stakes ethical decisions, such as by splitting a budget proportionally.