12 ideas
| 15375 | If terms change their designations in different states, they are functions from states to objects [Fitting] |
| Full Idea: The common feature of every designating term is that designation may change from state to state - thus it can be formalized by a function from states to objects. | |
| From: Melvin Fitting (Intensional Logic [2007], 3) | |
| A reaction: Specifying the objects sounds OK, but specifying states sounds rather tough. |
| 15376 | Intensional logic adds a second type of quantification, over intensional objects, or individual concepts [Fitting] |
| Full Idea: To first order modal logic (with quantification over objects) we can add a second kind of quantification, over intensions. An intensional object, or individual concept, will be modelled by a function from states to objects. | |
| From: Melvin Fitting (Intensional Logic [2007], 3.3) |
| 15378 | Awareness logic adds the restriction of an awareness function to epistemic logic [Fitting] |
| Full Idea: Awareness logic enriched Hintikka's epistemic models with an awareness function, mapping each state to the set of formulas we are aware of at that state. This reflects some bound on the resources we can bring to bear. | |
| From: Melvin Fitting (Intensional Logic [2007], 3.6.1) | |
| A reaction: [He cites Fagin and Halpern 1988 for this] |
| 15379 | Justication logics make explicit the reasons for mathematical truth in proofs [Fitting] |
| Full Idea: In justification logics, the logics of knowledge are extended by making reasons explicit. A logic of proof terms was created, with a semantics. In this, mathematical truths are known for explicit reasons, and these provide a measure of complexity. | |
| From: Melvin Fitting (Intensional Logic [2007], 3.6.1) |
| 11026 | Classical logic is deliberately extensional, in order to model mathematics [Fitting] |
| Full Idea: Mathematics is typically extensional throughout (we write 3+2=2+3 despite the two terms having different meanings). ..Classical first-order logic is extensional by design since it primarily evolved to model the reasoning of mathematics. | |
| From: Melvin Fitting (Intensional Logic [2007], §1) |
| 11028 | λ-abstraction disambiguates the scope of modal operators [Fitting] |
| Full Idea: λ-abstraction can be used to abstract and disambiguate a predicate. De re is [λx◊P(x)](f) - f has the possible-P property - and de dicto is ◊[λxP(x)](f) - possibly f has the P-property. Also applies to □. | |
| From: Melvin Fitting (Intensional Logic [2007], §3.3) | |
| A reaction: Compare the Barcan formula. Originated with Church in the 1930s, and Carnap 1947, but revived by Stalnaker and Thomason 1968. Because it refers to the predicate, it has a role in intensional versions of logic, especially modal logic. |
| 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. |
| 15377 | Definite descriptions pick out different objects in different possible worlds [Fitting] |
| Full Idea: Definite descriptions pick out different objects in different possible worlds quite naturally. | |
| From: Melvin Fitting (Intensional Logic [2007], 3.4) | |
| A reaction: A definite description can pick out the same object in another possible world, or a very similar one, or an object which has almost nothing in common with the others. |
| 15710 | Bohr explained the periodic table and chemical properties of elements, using the quantum atom [Kumar] |
| Full Idea: Bohr used the quantum atom to explain the periodic table and the chemical properties of the elements. ...It was his new theory about the arrangement of electrons inside atoms that explained the placing and grouping of elements in the periodic table. | |
| From: Manjit Kumar (Quantum: Einstein and Bohr [2008], Ch 04) | |
| A reaction: (second sentence p.133) This is Exhibit A for the idea that essences are explanatory, and are discovered by scientists. The moot point would be whether it is appropriate to describe electron shells as part of the 'essence' of an atom. |
| 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. |