Aristotle the founder of traditional logic represented these 4 standard form categorical proposition by using the letters A,E,I,O respectively. He symbolized them as presented below and derived from the first two vowels of the latin verbs ‘’AFFRIMO’’ (I affirm) for A and I and ‘’NEGO’’(I deny) for E and O. They could be illustrated as follows;

Universal affirmative    A=All is P = All boys are thieves

Universal negative        E=No Sis P = No girls are prostitutes

Particular affirmative   I=Some S is P =some parents are farmers

Particular negative       O=some is not P =some ladies are not pretty persons