# The elements of deductive logic

At the Clarendon Press, 1867 - Logic - 192 pages

### Popular passages

Page 115 - If A is B, C is D ; and if E is F, G is H ; But either C is not D, or G is not H ; Therefore either A is not B, or E is not F.
Page 137 - to allow every man an unbounded freedom of speech must always be, on the whole, advantageous to the State ; for it is highly conducive to the interests of the Community, that each individual should enjoy a liberty perfectly unlimited, of expressing his sentiments.
Page 62 - Thus, for" example, he to whom the geometrical proposition, that the angles of a triangle are together equal to two right angles...
Page 158 - In a higher world it is otherwise; but here below to live is to change, and to be perfect is to have changed often.
Page 143 - A servant who was roasting a stork for his master was prevailed upon by his sweetheart to cut off a leg for her to eat. When the bird came upon table, the master desired to know what was become of the other leg. The man answered that storks had never more than one leg.
Page 5 - Logic is both a science and an art ; it is a science inasmuch as, by analyzing the elements, principles, and structure of arguments, it teaches us how to discover their truth or detect their fallacies, and point out the sources of such errors. It is an art, inasmuch as it teaches...
Page 99 - Barbara, Celarent, Darii, Ferioque, prioris; Cesare, Camestres, Festino, Baroko, secundae; Tertia, Darapti, Disamis, Datisi, Felapton, Bokardo, Ferison, habet ; Quarta insuper addit Bramantip, Camenes, Dimaris, Fesapo, Fresison.
Page 132 - ... which, as already noticed, is one case of the fallacy of ambiguous terms. Thus to argue, because there are certain points of resemblance between the development of the individual and the development of the race, that, therefore, since the individual dies, the race will probably die also, or, because there are certain points of resemblance between the earth and the other planets, that, therefore, the other planets are certainly, or very probably, inhabited, would both be instances of false analogy,...