Changes

Converting a proposition without changing its quantity is called ''simple conversion''. When the quantity is reduced, as in the universal affirmative, it is called ''conversion per accidens''.

Converting a proposition without changing its quantity is called ''simple conversion''. When the quantity is reduced, as in the universal affirmative, it is called ''conversion per accidens''.

<ref>There is another kind of conversion omitted by Aristotle, but included within the scope of Aristotelian logic, called ''conversion by contraposition'', where the term contradictory to the predicate is given as the subject, and the quality of the proposition changed. thus 'All animals are sentient beings, therefore, a non-sentient being is not an animal.'<ref>  

<ref>There is another kind of conversion omitted by Aristotle, but included within the scope of Aristotelian logic, called ''conversion by contraposition'', where the term contradictory to the predicate is given as the subject, and the quality of the proposition changed. thus 'All animals are sentient beings, therefore, a non-sentient being is not an animal.'</ref>  

===Structure of syllogisms===

===Structure of syllogisms===