This paper examines the main ideas on syllogism in the logical systems of Aristotle, Stoics and Avveros. Aristotle, is the firts philosopher who formulated a system of logic. . He influenced many philosophers in this respect in the subsequent centuries. Aristotle gives an extreme importance to establishing the proof through syllogism which consists of two propositions or premises and conclusion. Aristotle investigates categorical and component syllogistic but not conditional one. According to Aristotle, there are three forms of syllogism. Stoics examine conditional syllogism. According to the latter, conditional syllogism consists of disjunctive and hypothetical syllogisms. Averroes is the most important of the commentators of Aristotle. However, he examines categorical and conditional syllogisms, too.

This paper examines the main ideas on syllogism in the logical systems of Aristotle, Stoics and Avveros. Aristotle, is the firts philosopher who formulated a system of logic. . He influenced many philosophers in this respect in the subsequent centuries. Aristotle gives an extreme importance to establishing the proof through syllogism which consists of two propositions or premises and conclusion. Aristotle investigates categorical and component syllogistic but not conditional one. According to Aristotle, there are three forms of syllogism. Stoics examine conditional syllogism. According to the latter, conditional syllogism consists of disjunctive and hypothetical syllogisms. Averroes is the most important of the commentators of Aristotle. However, he examines categorical and conditional syllogisms, too.