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| ==Selection 10== | | ==Selection 10== |
| | | |
− | <pre> | + | <blockquote> |
− | | The Signs for Multiplication (cont.)
| + | <p>'''The Signs for Multiplication''' (cont.)<p> |
− | |
| + | |
− | | The sum 'x' + 'x' generally denotes no logical term.
| + | <p>The sum 'x' + 'x' generally denotes no logical term. But 'x',<sub>∞</sub> + 'x',<sub>∞</sub> may be considered as denoting some two 'x's.</p> |
− | | But 'x',_oo + 'x',_oo may be considered as denoting
| + | |
− | | some two 'x's.
| + | <p>It is natural to write:</p> |
− | |
| + | |
− | | It is natural to write:
| + | : <p>'x' + 'x' = !2!.'x'</p> |
− | |
| + | |
− | | 'x' + 'x' = !2!.'x'
| + | <p>and</p> |
− | |
| + | |
− | | and
| + | : <p>'x',<sub>∞</sub> + 'x',<sub>∞</sub> = !2!.'x',<sub>∞</sub></p> |
− | |
| + | |
− | | 'x',_oo + 'x',_oo = !2!.'x',_oo
| + | <p>where the dot shows that this multiplication is invertible.</p> |
− | |
| + | |
− | | where the dot shows that this multiplication is invertible.
| + | <p>We may also use the antique figures so that:</p> |
− | |
| + | |
− | | We may also use the antique figures so that:
| + | : <p>!2!.'x',<sub>∞</sub> = `2`'x'</p> |
− | |
| + | |
− | | !2!.'x',_oo = `2`'x'
| + | <p>just as</p> |
− | |
| + | |
− | | just as
| + | : <p>!1!<sub>∞</sub> = `1`.</p> |
− | |
| + | |
− | | !1!_oo = `1`.
| + | <p>Then `2` alone will denote some two things.</p> |
− | |
| + | |
− | | Then `2` alone will denote some two things.
| + | <p>But this multiplication is not in general commutative, and only becomes so when it affects a relative which imparts a relation such that a thing only bears it to ''one'' thing, and one thing ''alone'' bears it to a thing.</p> |
− | |
| + | |
− | | But this multiplication is not in general commutative,
| + | <p>For instance, the lovers of two women are not the same as two lovers of women, that is:</p> |
− | | and only becomes so when it affects a relative which
| + | |
− | | imparts a relation such that a thing only bears it
| + | : <p>'l'`2`.w</p> |
− | | to 'one' thing, and one thing 'alone' bears it to
| + | |
− | | a thing.
| + | and |
− | |
| + | |
− | | For instance, the lovers of two women are not
| + | : <p>`2`.'l'w</p> |
− | | the same as two lovers of women, that is:
| + | |
− | |
| + | <p>are unequal;</p> |
− | | 'l'`2`.w
| + | |
− | |
| + | <p>but the husbands of two women are the same as two husbands of women, that is:</p> |
− | | and
| + | |
− | |
| + | : <p>'h'`2`.w = `2`.'h'w</p> |
− | | `2`.'l'w
| + | |
− | |
| + | <p>and in general:</p> |
− | | are unequal;
| + | |
− | |
| + | : <p>'x',`2`.'y' = `2`.'x','y'.</p> |
− | | but the husbands of two women are the
| + | |
− | | same as two husbands of women, that is:
| + | <p>(Peirce, CP 3.75).</p> |
− | |
| + | </blockquote> |
− | | 'h'`2`.w = `2`.'h'w
| |
− | |
| |
− | | and in general:
| |
− | |
| |
− | | 'x',`2`.'y' = `2`.'x','y'.
| |
− | |
| |
− | | C.S. Peirce, CP 3.75
| |
− | |
| |
− | | Charles Sanders Peirce,
| |
− | |"Description of a Notation for the Logic of Relatives,
| |
− | | Resulting from an Amplification of the Conceptions of Boole's Calculus of Logic",
| |
− | |'Memoirs of the American Academy', Volume 9, pages 317-378, 26 January 1870,
| |
− | |'Collected Papers' (CP 3.45-149), 'Chronological Edition' (CE 2, 359-429).
| |
− | </pre> | |
| | | |
| ===Commentary Note 10.1=== | | ===Commentary Note 10.1=== |