Question

What is the purpose of the square of opposition?

Explain how the square of opposition is used to translate statements into standard form claims and corresponding standard for claims including descriotion of the relationships that are depicted withing the square.

Answer 1

The square of opposition is a chart that was introduced within classical (categorical) logic to represent the logical relationships holding between certain propositions in virtue of their form.

Here there is a collection of logical relationships traditionally embodied in a square diagram.

Use the traditional square of opposition, together with conversion, obversion and contraposition to prove that the following arguments are valid.

1) No feminists are male chauvinist pigs.
Therefore some advocates of equality are not anti-feminists.

(note: "advocates of equality" and "male chauvinist pigs" are term compliments)

2) It is false that no unhealthy things to ingest are food additives. Therefore, some food additives are not healthy things to ingest.