13 ideas
| 19426 | 'Nominal' definitions just list distinguishing characteristics [Leibniz] |
| Full Idea: A 'nominal' definition is nothing more than an enumeration of the sufficient distinguishing characteristics. | |
| From: Gottfried Leibniz (Reflections on Knowledge, Truth and Ideas [1684], p.284) | |
| A reaction: Not wholly clear. Are these actual distinguishing characteristics, or potential ones? Could DNA be part of a human's nominal definition (for an unidentified corpse, perhaps). |
| 8568 | A property is merely a constituent of laws of nature; temperature is just part of thermodynamics [Mellor] |
| Full Idea: Being a constituent of probabilistic laws of nature is all there is to being a property. There is no more to temperature than the thermodynamics and other laws they occur in. | |
| From: D.H. Mellor (Properties and Predicates [1991], 'Props') | |
| A reaction: How could thermodynamics be worked out without a prior concept of temperature? I think it is at least plausible to deny that there are any 'laws' of nature. But even Quine can't deny that some things are too hot to touch. |
| 8564 | There is obviously a possible predicate for every property [Mellor] |
| Full Idea: To every property there obviously corresponds a possible predicate applying to all and only those particulars with that property. | |
| From: D.H. Mellor (Properties and Predicates [1991], 'Intro') | |
| A reaction: This doesn't strike me as at all obvious. If nature dictates the properties, there may be vastly more than any human language could cope with. It is daft to say that a property can only exist if humanity can come up with a predicate for it. |
| 8566 | We need universals for causation and laws of nature; the latter give them their identity [Mellor] |
| Full Idea: I take the main reason for believing in contingent universals to be the roles they play in causation and in laws of nature, and those laws are what I take to give those universals their identity. | |
| From: D.H. Mellor (Properties and Predicates [1991], 'Props') | |
| A reaction: He agrees with Armstrong. Sounds a bit circular - laws are built on universals, and universals are identified by laws. It resembles a functionalist account of mental events. I think it is wrong. A different account of laws will be needed... |
| 8565 | If properties were just the meanings of predicates, they couldn't give predicates their meaning [Mellor] |
| Full Idea: One reason for denying that properties just are the meanings of our predicates is that, if they were, they could not give our predicates their meanings. | |
| From: D.H. Mellor (Properties and Predicates [1991], 'Props') | |
| A reaction: Neither way round sounds quite right to me. Predicate nominalism is wrong, but what is meant by a property 'giving' a predicate its meaning? It doesn't seem to allow room for error in our attempts to name the properties. |
| 13768 | Validity can preserve certainty in mathematics, but conditionals about contingents are another matter [Edgington] |
| Full Idea: If your interest in logic is confined to applications to mathematics or other a priori matters, it is fine for validity to preserve certainty, ..but if you use conditionals when arguing about contingent matters, then great caution will be required. | |
| From: Dorothy Edgington (Conditionals [2001], 17.2.1) |
| 13770 | There are many different conditional mental states, and different conditional speech acts [Edgington] |
| Full Idea: As well as conditional beliefs, there are conditional desires, hopes, fears etc. As well as conditional statements, there are conditional commands, questions, offers, promises, bets etc. | |
| From: Dorothy Edgington (Conditionals [2001], 17.3.4) |
| 13764 | Are conditionals truth-functional - do the truth values of A and B determine the truth value of 'If A, B'? [Edgington] |
| Full Idea: Are conditionals truth-functional - do the truth values of A and B determine the truth value of 'If A, B'? Are they non-truth-functional, like 'because' or 'before'? Do the values of A and B, in some cases, leave open the value of 'If A,B'? | |
| From: Dorothy Edgington (Conditionals [2001], 17.1) | |
| A reaction: I would say they are not truth-functional, because the 'if' asserts some further dependency relation that goes beyond the truth or falsity of A and B. Logical ifs, causal ifs, psychological ifs... The material conditional ⊃ is truth-functional. |
| 13765 | 'If A,B' must entail ¬(A & ¬B); otherwise we could have A true, B false, and If A,B true, invalidating modus ponens [Edgington] |
| Full Idea: If it were possible to have A true, B false, and If A,B true, it would be unsafe to infer B from A and If A,B: modus ponens would thus be invalid. Hence 'If A,B' must entail ¬(A & ¬B). | |
| From: Dorothy Edgington (Conditionals [2001], 17.1) | |
| A reaction: This is a firm defence of part of the truth-functional view of conditionals, and seems unassailable. The other parts of the truth table are open to question, though, if A is false, or they are both true. |
| 19424 | Knowledge needs clarity, distinctness, and adequacy, and it should be intuitive [Leibniz] |
| Full Idea: Knowledge is either obscure or clear; clear ideas are either indistinct or distinct; distinct ideas are either adequate or inadequate, symbolic or intuitive; perfect knowledge is that which is both adequate and intuitive. | |
| From: Gottfried Leibniz (Reflections on Knowledge, Truth and Ideas [1684], p.283) | |
| A reaction: This is Leibniz's expansion of Descartes's idea that knowledge rests on 'clear and distinct conceptions'. The ultimate target seems to be close to an Aristotelian 'real definition', which is comprehensive and precise. Does 'intuitive' mean coherent? |
| 19427 | True ideas represent what is possible; false ideas represent contradictions [Leibniz] |
| Full Idea: An idea is true if what it represents is possible; false if the representation contains a contradiction. | |
| From: Gottfried Leibniz (Reflections on Knowledge, Truth and Ideas [1684], p.287) | |
| A reaction: Odd in the analytic tradition to talk of a single idea or concept (rather than a proposition or utterance) as being 'true'. But there is clearly a notion of valid or legitimate or useful concepts here. Hilbert said true just meant non-contradictory. |
| 19425 | In the schools the Four Causes are just lumped together in a very obscure way [Leibniz] |
| Full Idea: In the schools the four causes are lumped together as material, formal, efficient, and final causes, but they have no clear definitions, and I would call such a judgment 'obscure'. | |
| From: Gottfried Leibniz (Reflections on Knowledge, Truth and Ideas [1684], p.283) | |
| A reaction: He picks this to illustrate what he means by 'obscure', so he must feel strongly about it. Elsewhere Leibniz embraces efficient and final causes, but says little of the other two. This immediately become clearer as the Four Modes of Explanation. |
| 8567 | Singular causation requires causes to raise the physical probability of their effects [Mellor] |
| Full Idea: Singular causation entails physical probabilities or chances. ...Causal laws require causes to raise their effects' chances, as when fires have a greater chance of occurring when explosions do. | |
| From: D.H. Mellor (Properties and Predicates [1991], 'Props') | |
| A reaction: It seems fairly obvious that a probability can be increased without actually causing something. Just after a harmless explosion is a good moment for arsonists, especially if Mellor will be the investigating officer. |