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Review of P. Coffey, “The Science of Logic”: Difference between revisions
Review of P. Coffey, “The Science of Logic” (view source)
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Mr Coffey, like many logicians, draws great advantage from an unclear way of expressing himself; for if you cannot tell whether he means to say “Yes” or “No”, it is difficult to argue against him. However, even through his foggy expression, many grave mistakes can be recognised clearly enough; and I propose to give a list of some of the most striking ones, and would advise the student of Logic to trace these mistakes and their consequences in other books on Logic also. (The numbers in brackets indicate the pages of Mr Coffey’s book—volume I.—where a mistake occurs for the first time; the illustrative examples are my own). | Mr Coffey, like many logicians, draws great advantage from an unclear way of expressing himself; for if you cannot tell whether he means to say “Yes” or “No”, it is difficult to argue against him. However, even through his foggy expression, many grave mistakes can be recognised clearly enough; and I propose to give a list of some of the most striking ones, and would advise the student of Logic to trace these mistakes and their consequences in other books on Logic also. (The numbers in brackets indicate the pages of Mr Coffey’s book—volume I.—where a mistake occurs for the first time; the illustrative examples are my own). | ||
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<ol style="list-style-type: upper-roman;"><li>[36] The author believes that all propositions are of the subject-predicate form.</li> | |||
<li>[31] He believes that reality is changed by becoming an object of our thoughts. | |||
<li>[6] He confounds the copula “is” with the word “is” expressing identity. (The word “is” has obviously different meanings in the propositions— | |||
<ul style="list-style-type: none;"><li>“Twice two is four”</li> | |||
: | <li>and “Socrates is mortal.”)</li></ul></li> | ||
<li>[46] He confounds things with the classes to which they belong. (A man is obviously something quite different from mankind.)</li> | |||
<li>[48] He confounds classes and complexes. (Mankind is a class whose elements are men; but a library is not a class whose elements are books, because books become parts of a library only by standing in certain spatial relations to one another—while classes are independent of the relations between their members.)</li> | |||
<li>[47] He confounds complexes and sums. (Two plus two is four, but four is not a complex of two and itself.)</li> | |||
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This list of mistakes could be extended a good deal. | This list of mistakes could be extended a good deal. | ||