The Elements of Logic: In Four Books ... |
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according affirmed antecedent appear applied aqua regia arrive bodies called certainty combinations compared complex ideas complex notions compound comprehended conceptions conclusion connexion consequent consideration considered constitute copula deduced definitions demonstration denote derived discoveries disjunctive proposition distinct distinctly distinguished division enthymemes equal established Euclid evident existence experience explained express farther figure foundation frame furnish genus gisms Hence human knowledge hypothetical syllogism innu insomuch instance intermediate ideas intuitive invention ject judgments kind known ledge logicians manner mathematicians means method middle term mind modus ponens modus tollens natural philosophy necessarily neral notice objects observe ourselves particular perceptions plain powers predicate premises principles proceed proper properties proposition Rehoboam relations rules self-evident simple ideas sion sorites species stand step substances suppose syllogisms thence ther things thoughts tion trace true truth understanding unfolding universal universal proposition whence whole wholly words
Popular passages
Page 150 - Just so it is in the mind ; would you have a man reason well, you must use him to it betimes, exercise his mind in observing the connection of ideas and following them in train. Nothing does this better than mathematics, which therefore I think should be taught all those who have the time and opportunity, not so much to' make them mathematicians as to make them reasonable creatures...
Page 150 - I have mentioned mathematics as a way to settle in the mind a habit of reasoning closely and in train ; not that I think it necessary that all men should be deep mathematicians, but that, having got the way of reasoning, which that study necessarily brings the mind to, they might be able to transfer it to other parts of knowledge as they shall have occasion.
Page 151 - ... and following them in train. Nothing does this better than mathematics; which, therefore, I think should be taught all those who have the time and opportunity ; not so much to make them mathematicians, as to make them reasonable creatures ; for though we all call ourselves so, because we are born to it* if we please : yet we may truly say, nature gives us but the seeds of it ; we are born to be, if we please, rational creatures, but it" is use and exercise only that makes us so, and we are, indeed,...
Page 98 - Thus, that the whole is greater than any of its parts, is an intuitive judgment; nothing more being required to convince us of its truth than an attention to the ideas of whole and part. And this too is the...
Page 119 - ... understood ; upon comparing the ideas together, the agreement or disagreement asserted is either immediately perceived, or found to lie beyond the present reach of the lersunding.
Page 160 - If things equal to one and the same thing are equal to one another; these two triangles, each equal to a square whose side is three inches, are also equal between themselves.
Page 65 - Sign of the Idea excited in me by fuch an Approach, nor have any doubt but it denotes the fame Perception in my Mind as in theirs. For we are naturally led to imagine, that the fame Objects operate alike upon the Organs of the human Body, and produce an Uniformity of Senfations.
Page 88 - But in order to the better underftanding of what follows, it will be necefiary to obferve, that there is a certain Gradation in the Compofition of our Ideas. The Mind of Man is very limited in its Views, and cannot take in a great Number of Objects at once. We are therefore fain to proceed by Steps, and make our firft Advances fubfervient to thofe which follow.
Page 158 - But it often happens, that some one of the premises is not only an evident truth, 'but also familiar and in the minds of all men ; in which case it is usually omitted, whereby we have an imperfect syllogism, that seems to be made up of only two proposition.
Page 150 - ... that, having got the way of reasoning, which that study necessarily brings the mind to, they might be able to transfer it to other parts of knowledge, as they shall have occasion. For, in all sorts of reasoning, every single argument should be managed as a mathematical demonstration: the connexion and dependence of ideas should be followed, till the mind is brought to the source on which it bottoms, and observes the coherence all along, though in proofs of probability one such train is not enough...