10 ideas
| 8083 | Boole applied normal algebra to logic, aiming at an algebra of thought [Boole, by Devlin] |
| Full Idea: Boole proposed to use the entire apparatus of a school algebra class, with operations such as addition and multiplication, methods to solve equations, and the like, to produce an algebra of thought. | |
| From: report of George Boole (The Laws of Thought [1854]) by Keith Devlin - Goodbye Descartes Ch.3 | |
| A reaction: The Stoics didn’t use any algebraic notation for their study of propositions, so Boole's idea launched full blown propositional logic, and the rest of modern logic followed. Nice one. |
| 7727 | Boole's notation can represent syllogisms and propositional arguments, but not both at once [Boole, by Weiner] |
| Full Idea: Boole introduced a new symbolic notation in which it was possible to represent both syllogisms and propositional arguments, ...but not both at once. | |
| From: report of George Boole (The Laws of Thought [1854], Ch.3) by Joan Weiner - Frege | |
| A reaction: How important is the development of symbolic notations for the advancement of civilisations? Is there a perfect notation, as used in logical heaven? |
| 8686 | Boole made logic more mathematical, with algebra, quantifiers and probability [Boole, by Friend] |
| Full Idea: Boole (followed by Frege) began to turn logic from a branch of philosophy into a branch of mathematics. He brought an algebraic approach to propositions, and introduced the notion of a quantifier and a type of probabilistic reasoning. | |
| From: report of George Boole (The Laws of Thought [1854], 3.2) by Michèle Friend - Introducing the Philosophy of Mathematics | |
| A reaction: The result was that logic not only became more mathematical, but also more specialised. We now have two types of philosopher, those steeped in mathematical logic and the rest. They don't always sing from the same songsheet. |
| 22277 | Boole's method was axiomatic, achieving economy, plus multiple interpretations [Boole, by Potter] |
| Full Idea: Boole's work was an early example of the axiomatic method, whereby intellectual economy is achieved by studying a set of axioms in which the primitive terms have multiple interpretations. | |
| From: report of George Boole (The Laws of Thought [1854]) by Michael Potter - The Rise of Analytic Philosophy 1879-1930 02 'Boole' | |
| A reaction: Unclear about this. I suppose the axioms are just syntactic, and a range of semantic interpretations can be applied. Are De Morgan's Laws interpretations, or implications of the syntactic axioms? The latter, I think. |
| 13174 | A piece of flint contains something resembling perceptions and appetites [Leibniz] |
| Full Idea: I don't say that bodies like flint, which are commonly called inanimate, have perceptions and appetition; rather they have something of that sort in them, like worms are in cheese. | |
| From: Gottfried Leibniz (Letters to Johann Bernoulli [1699], 1698.12.17) | |
| A reaction: Leibniz is caricatured as thinking that stones are full of little active minds, but he nearly always says that what he is proposing is 'like' or 'analogous to' that. His only real point is that nature is active, as seen in the appetites of animals. |
| 13175 | Entelechies are analogous to souls, as other minds are analogous to our own minds [Leibniz] |
| Full Idea: Just as we somehow conceive other souls and intelligences on analogy with our own souls, I wanted whatever other primitive entelechies there may be remote from our senses to be conceived on analogy with souls. They are not conceived perfectly. | |
| From: Gottfried Leibniz (Letters to Johann Bernoulli [1699], 1698.12.17) | |
| A reaction: This is the clearest evidence I can find that Leibniz does not think of monads as actually being souls. He is struggling to explain their active character. Garber thinks that Leibniz hasn't arrived at proper monads at this date. |
| 13172 | What we cannot imagine may still exist [Leibniz] |
| Full Idea: It does not follow that what we can't imagine does not exist. | |
| From: Gottfried Leibniz (Letters to Johann Bernoulli [1699], 1698.11.18) | |
| A reaction: This just establishes the common sense end of the debate - that you cannot just use your imagination as the final authority on what exists, or what is possible. |
| 13173 | Death is just the contraction of an animal [Leibniz] |
| Full Idea: Death is nothing but the contraction of an animal, just as generation is nothing but its unfolding. | |
| From: Gottfried Leibniz (Letters to Johann Bernoulli [1699], 1698.11.18) | |
| A reaction: This is possibly the most bizarre view that I have found in Leibniz. He seemed to thing that if you burnt an animal on a bonfire, some little atom of life would remain among the ashes. I can't see why he would believe such a thing. |
| 1748 | Archelaus was the first person to say that the universe is boundless [Archelaus, by Diog. Laertius] |
| Full Idea: Archelaus was the first person to say that the universe is boundless. | |
| From: report of Archelaus (fragments/reports [c.450 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 02.Ar.3 |
| 5989 | Archelaus said life began in a primeval slime [Archelaus, by Schofield] |
| Full Idea: Archelaus wrote that life on Earth began in a primeval slime. | |
| From: report of Archelaus (fragments/reports [c.450 BCE]) by Malcolm Schofield - Archelaus | |
| A reaction: This sounds like a fairly clearcut assertion of the production of life by evolution. Darwin's contribution was to propose the mechanism for achieving it. We should honour the name of Archelaus for this idea. |