A reasoning flaw in which the conclusion is assumed — rather than established — by the premises. The argument "proves" its conclusion only by restating it in different words, so the premises and conclusion say the same thing and no independent evidence is offered. Classic LSAT example: "Reliable news sources are trustworthy because they consistently provide information that can be relied upon." LSAT phrasing: "presupposes what it sets out to establish" or "assumes the truth of what it is trying to prove."