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An introductory text-book of logic - Mellone, Sydney - Rare Books at ...

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70<br />

OPPOSITION OF PROPOSITIONS.<br />

includes the truth <strong>of</strong> the particular. But if we only<br />

know the truth <strong>of</strong> the particulars i.e., only know th<strong>at</strong><br />

&quot;<br />

<strong>at</strong> least some S is or th<strong>at</strong><br />

P,&quot;<br />

P<br />

&quot;<br />

&quot;<br />

<strong>at</strong> least some S is not<br />

we do not know whether the respective universals<br />

are true or not.<br />

The six rel<strong>at</strong>ions which we have explained are shown<br />

in a diagram called the square <strong>of</strong> opposition, which<br />

would be more accur<strong>at</strong>ely called the<br />

&quot;<br />

square <strong>of</strong> rel<strong>at</strong>ion.&quot;<br />

sub-contraries O<br />

Fig. 6.<br />

The results <strong>of</strong> this section may be summed up in the<br />

following table :<br />

EXERCISE III.<br />

Give the contradictory <strong>of</strong> each proposition contained in<br />

Exercise II., questions i to n inclusive, and 14.<br />

[Before the contradictory <strong>of</strong> a proposition can be given,<br />

it must <strong>of</strong> course be expressed in strict <strong>logic</strong>al form.]

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