21 ideas
| 21544 | It seems that when a proposition is false, something must fail to subsist [Russell] |
| Full Idea: It seems that when a proposition is false, something does not subsist which would subsist if the proposition were true. | |
| From: Bertrand Russell (Meinong on Complexes and Assumptions [1904], p.76) | |
| A reaction: This looks to me like a commitment by Russell to the truthmaker principle. The negations of false propositions are made true by some failure of existence in the world. |
| 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) |
| 21539 | Excluded middle can be stated psychologically, as denial of p implies assertion of not-p [Russell] |
| Full Idea: The law of excluded middle may be stated in the form: If p is denied, not-p must be asserted; this form is too psychological to be ultimate, but the point is that it is significant and not a mere tautology. | |
| From: Bertrand Russell (Meinong on Complexes and Assumptions [1904], p.41) | |
| A reaction: 'Psychology' is, of course, taboo, post-Frege, though I think it is interesting. Stated in this form the law looks more false than usual. I can be quite clear than p is unacceptable, but unclear about its contrary. |
| 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. |
| 21538 | If two people perceive the same object, the object of perception can't be in the mind [Russell] |
| Full Idea: If two people can perceive the same object, as the possibility of any common world requires, then the object of an external perception is not in the mind of the percipient. | |
| From: Bertrand Russell (Meinong on Complexes and Assumptions [1904], p.33) | |
| A reaction: This is merely an assertion of the realist view, rather than an argument. I take representative realism to tell a perfectly good story that permits two subjective representations of the same object. |
| 21534 | The only thing we can say about relations is that they relate [Russell] |
| Full Idea: It may be doubted whether relations can be adequately characterised by anything except the fact that they relate. | |
| From: Bertrand Russell (Meinong on Complexes and Assumptions [1904], p.27) | |
| A reaction: We can characterise a rope that ties things together. If I say 'stand to his left', do I assume the existence of one of the relata and the relation, but without the second relata? How about 'you two stand over there, with him on the left'? |
| 21540 | Relational propositions seem to be 'about' their terms, rather than about the relation [Russell] |
| Full Idea: In some sense which it would be very desirable to define, a relational proposition seems to be 'about' its terms, in a way in which it is not about the relation. | |
| From: Bertrand Russell (Meinong on Complexes and Assumptions [1904], p.53) | |
| A reaction: Identifying how best to specify what a proposition is actually 'about' is a very illuminating mode of enquiry. You can't define 'underneath' without invoking a pair of objects to illustrate it. A proposition can still focus on the relation. |
| 21536 | When I perceive a melody, I do not perceive the notes as existing [Russell] |
| Full Idea: When, after hearing the notes of a melody, I perceive the melody, the notes are not presented as still existing. | |
| From: Bertrand Russell (Meinong on Complexes and Assumptions [1904], p.31) | |
| A reaction: This is a good example, supporting Meinong's idea that we focus on 'intentional objects', rather than actual objects. |
| 21535 | Objects only exist if they 'occupy' space and time [Russell] |
| Full Idea: Only those objects exist which have to particular parts of space and time the special relation of 'occupying' them. | |
| From: Bertrand Russell (Meinong on Complexes and Assumptions [1904], p.29) | |
| A reaction: He excepts space and time themselves. Clearly this doesn't advance our understanding much, but it points to a priority in our normal conceptual scheme. Is Russell assuming absolute space and time? |
| 21533 | Contingency arises from tensed verbs changing the propositions to which they refer [Russell] |
| Full Idea: Contingency derives from the fact that a sentence containing a verb in the present tense - or sometimes in the past or the future - changes its meaning continually as the present changes, and stands for different propositions at different times. | |
| From: Bertrand Russell (Meinong on Complexes and Assumptions [1904], p.26) | |
| A reaction: This immediately strikes me as a bad example of the linguistic approach to philosophy. As if we (like any animal) didn't have an apprehension prior to any language that most parts of experience are capable of change. |
| 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. |
| 21537 | I assume we perceive the actual objects, and not their 'presentations' [Russell] |
| Full Idea: I prefer to advocate ...that the object of a presentation is the actual external object itself, and not any part of the presentation at all. | |
| From: Bertrand Russell (Meinong on Complexes and Assumptions [1904], p.33) | |
| A reaction: Although I am a fan of the robust realism usually favoured by Russell, I think he is wrong. I take Russell to be frightened that once you take perception to be of 'presentations' rather than things, there is a slippery slope to anti-realism. Not so. |
| 21532 | Full empiricism is not tenable, but empirical investigation is always essential [Russell] |
| Full Idea: Although empiricism as a philosophy does not appear to be tenable, there is an empirical manner of investigating, which should be applied in every subject-matter | |
| From: Bertrand Russell (Meinong on Complexes and Assumptions [1904], p.22) | |
| A reaction: Given that early Russell loads his ontology with properties and propositions, this should come as no surprise, even if J.S. Mill was his godfather. |
| 3061 | Anaxarchus said that he was not even sure that he knew nothing [Anaxarchus, by Diog. Laertius] |
| Full Idea: Anaxarchus said that he was not even sure that he knew nothing. | |
| From: report of Anaxarchus (fragments/reports [c.340 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 09.10.1 |
| 21542 | Do incorrect judgements have non-existent, or mental, or external objects? [Russell] |
| Full Idea: Correct judgements have a transcendent object; but with regard to incorrect judgements, it remains to examine whether 1) the object is immanent, 2) there is no object, or 3) the object is transcendent. | |
| From: Bertrand Russell (Meinong on Complexes and Assumptions [1904], p.67) | |
| A reaction: Why is it that only Russell seems to have taken this problem seriously? Its solution gives the clearest possible indicator of how the mind relates to the world. |
| 21541 | The complexity of the content correlates with the complexity of the object [Russell] |
| Full Idea: Every property of the object seems to demand a strictly correlative property of the content, and the content, therefore, must have every complexity belonging to the object. | |
| From: Bertrand Russell (Meinong on Complexes and Assumptions [1904], p.55) | |
| A reaction: This claim gives a basis for his 'congruence' account of the correspondence theory of truth. It strikes me as false. If I talk of the 'red red robin', I don't mention the robin's feet. He ignores the psychological selection we make in abstraction. |
| 21543 | If p is false, then believing not-p is knowing a truth, so negative propositions must exist [Russell] |
| Full Idea: If p is a false affirmative proposition ...then it seems obvious that if we believe not-p we do know something true, so belief in not-p must be something which is not mere disbelief. This proves that there are negative propositions. | |
| From: Bertrand Russell (Meinong on Complexes and Assumptions [1904], p.75) | |
| A reaction: This evidently assumes excluded middle, but is none the worse for that. But it sounds suspiciously like believing there is no rhinoceros in the room. Does such a belief require a fact? |