The concept of rational comes from from the word “ratio,” which means when in someone's opinion something has a more positive than negative outcome, it's a rational choice; irrational would be the opposite of that. Since rationality is subjective, what is rational for one person's self-interest is probably irrational for someone else; that's why socialism, the ideal of doing the most good for the most people, is suspect as a method of making group decisions unless the group is highly homogeneous in its morals, values & beliefs. Most things that are rational are also logical because subjective goals can also be objectively true; for example, decisions based on knowledge, like when to mow the lawn, or how much money to save. It’s through a lack of facts or a biased interpretation that leads to rational but illogical conclusions: it may make rational sense to some people to sacrifice a goat to get their god's attention but it's illogical. Politics is certainly dominated by rational illogi