Formal Logic or, The Calculus of Inference, Necessary and Probable.

DE MORGAN, August.

Editore: Taylor and Walton, London, 1847

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TP + [iii]-vi = Preface + [vii]-xvi = Table of Contents + [1]-336 + [1]-8 = Publisher's ads. Octavo. First Edition. "De Morgan's work, which commenced in the 1840's, can be seen as the bridge between [the] older [Aristotelian] approach [to logic] and Boole's analytical formulation. Boole acknowledged his debt to De Morgan and Hamilton in the preface to his first logical work, 'The Mathematical Analysis of Logic' (1847)." (DSB under De Morgan). De Morgan's work, Formal Logic, published in 1847, is principally remarkable for his development of the numerically definite syllogism. The followers of Aristotle say that from two particular propositions such as Some M's are A's, and Some M's are B's nothing follows of necessity about the relation of the A's and B's. But they go further and say in order that any relation about the A's and B's may follow of necessity, the middle term must be taken universally in one of the premises. De Morgan pointed out that from Most M's are A's and Most M's are B's it follows of necessity that some A's are B's and he formulated the numerically formulated definite syllogism which puts this principle in an exact quantitative form. Suppose, for example, that the number of souls on board a steamer was 1000, that 500 were in the saloon, and 700 were lost. It follows of necessity, that at least 700 + 500 - 1000, that is, 200, saloon passengers were lost. This single principle suffices to prove the validity of all the Aristotelian moods. It is therefore a fundamental principle in necessary reasoning. Here then De Morgan had made a great advance by introducing quantification of the terms. Interestingly, the book is printed throughout using the "long s" (the eighth word in the book's title is, for instance, printed as Neceffary) - a practice that had been generally abandoned by British printers more than 50 years earlier. Publisher's later cloth binding (the six pages of ads present at the end of the book are dated November, 1853) with a printed spine label with faded gilt lettering. The terior is clean, tight and bright. ADDITIONAL PHOTOS AVAILABLE UPON REQUEST.

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• Titolo: Formal Logic or, The Calculus of Inference, Necessary and Probable.
• Editore: Taylor and Walton, London
• Data di pubblicazione: 1847
• Edizione: FIRST EDITION.
• Cataloghi dei venditori:
  • Philosophy & Religions