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| ===Commentary Note 11.20=== | | ===Commentary Note 11.20=== |
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− | We arrive at the last, for the time being, of Peirce's statements about the "number of" map. | + | We arrive at the last of Peirce's statements about the "number of" map that we singled out above: |
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| + | '''NOF 4''' |
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| {| align="center" cellspacing="6" width="90%" <!--QUOTE--> | | {| align="center" cellspacing="6" width="90%" <!--QUOTE--> |
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− | <p>The conception of multiplication we have adopted is that of the application of one relation to another. …</p> | + | <p>The conception of multiplication we have adopted is that of the application of one relation to another. …</p> |
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− | <p>Even ordinary numerical multiplication involves the same idea, for 2 × 3 is a pair of triplets, and 3 × 2 is a triplet of pairs, where "triplet of" and "pair of" are evidently relatives.</p> | + | <p>Even ordinary numerical multiplication involves the same idea, for <math>~2 \times 3~</math> is a pair of triplets, and <math>~3 \times 2~</math> is a triplet of pairs, where "triplet of" and "pair of" are evidently relatives.</p> |
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| <p>If we have an equation of the form:</p> | | <p>If we have an equation of the form:</p> |
− | | + | |- |
− | : <p>''xy'' = ''z''</p>
| + | | align="center" | <math>xy ~=~ z</math> |
− | | + | |- |
− | <p>and there are just as many x's per y as there are ''per'' things, things of the universe, then we have also the arithmetical equation:</p> | + | | |
− | | + | <p>and there are just as many <math>x\!</math>'s per <math>y\!</math> as there are, ''per'' things, things of the universe, then we have also the arithmetical equation:</p> |
− | : <p>[''x''][''y''] = [''z''].</p>
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− | | + | | align="center" | <math>[x][y] ~=~ [z].</math> |
| + | |- |
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| <p>(Peirce, CP 3.76).</p> | | <p>(Peirce, CP 3.76).</p> |
| |} | | |} |