24 ideas
4739 | In "if and only if" (iff), "if" expresses the sufficient condition, and "only if" the necessary condition [Engel] |
Full Idea: Necessary and sufficient conditions are usually expressed by "if and only if" (abbr. "iff"), where "if" is the sufficient condition, and "only if" is the necessary condition. | |
From: Pascal Engel (Truth [2002], §1.1) | |
A reaction: 'I take my umbrella if and only if it is raining' (oh, and if I'm still alive). There may be other necessary conditions than the one specified. Oh, and I take it if my wife slips it into my car… |
4737 | Are truth-bearers propositions, or ideas/beliefs, or sentences/utterances? [Engel] |
Full Idea: The tradition of the Stoics and Frege says that truth-bearers are propositions, Descartes and the classical empiricist say they are ideas or beliefs, and Ockham and Quine say they are sentences or utterances. | |
From: Pascal Engel (Truth [2002], §1.1) | |
A reaction: I'm with propositions, which are unambiguous, can be expressed in a variety of ways, embody the 'logical form' of sentences, and could be physically embodied in brains (the language of thought?). |
4750 | The redundancy theory gets rid of facts, for 'it is a fact that p' just means 'p' [Engel] |
Full Idea: The redundancy theory gets rid of facts, for 'it is a fact that p' just means 'p'. | |
From: Pascal Engel (Truth [2002], §2.2) | |
A reaction: But then when you ask what p means, you have to give the truth-conditions for its assertion, and you find you have to mention the facts after all. |
4744 | We can't explain the corresponding structure of the world except by referring to our thoughts [Engel] |
Full Idea: The correspondence theory implies displaying an identity or similarity of structure between the contents of thoughts and the way the world is structured, but we seem only to be able to say that the world's structure corresponds to our thoughts. | |
From: Pascal Engel (Truth [2002], §1.2) | |
A reaction: I don't accept this. The structure of the world gives rise to our thoughts. There is an epistemological problem here (big time!), but that doesn't alter the metaphysical situation of what truth is supposed to be, which is correspondence. |
4738 | The coherence theory says truth is an internal relationship between groups of truth-bearers [Engel] |
Full Idea: The coherence theory of truth says that it is a relationship between truth-bearers themselves, that is between propositions or beliefs or sentences. | |
From: Pascal Engel (Truth [2002], §1.1) | |
A reaction: We immediately begin to wonder how many truth-bearers are required. Two lies can be coherent. It is hard to make thousands of lies coherent, but not impossible. What fixes the critical number. 'All possible propositions' is not much help. |
4745 | Any coherent set of beliefs can be made more coherent by adding some false beliefs [Engel] |
Full Idea: Any coherent set of beliefs can be made more coherent by adding to it one or more false beliefs. | |
From: Pascal Engel (Truth [2002], §1.3) | |
A reaction: A simple but rather devastating point. It is the policeman manufacturing a bogus piece of evidence to clinch the conviction, the scientist faking a single observation to fill in the last corner of a promising theory. |
4753 | Deflationism seems to block philosophers' main occupation, asking metatheoretical questions [Engel] |
Full Idea: Deflationism about truth seems to deprive us of any hope of asking genuinely metatheoretical questions, which are the questions that occupy philosophers most of the time. | |
From: Pascal Engel (Truth [2002], §2.5) | |
A reaction: This seems like the best reason for moving from deflationism to at least minimalism. Clearly one can talk meaningfully about the success of assertions and theories. You can say a sentence is true, but not assert it. |
4755 | Deflationism cannot explain why we hold beliefs for reasons [Engel] |
Full Idea: The deflationist view is silent about the fact that our assertions and beliefs are generally made or held for certain reasons. | |
From: Pascal Engel (Truth [2002], §2.5) | |
A reaction: The point here must be that I attribute strength to my beliefs, depending on how much support I have for them - how much support for their real truth. I scream "That's really TRUE!" when I have very good reasons. |
4751 | Maybe there is no more to be said about 'true' than there is about the function of 'and' in logic [Engel] |
Full Idea: We could compare the status of 'true' with the status of the logical operator 'and' in logic. Once we have explained how it functions to conjoin two propositions, there is not much more to be said about it. | |
From: Pascal Engel (Truth [2002], §2.4) | |
A reaction: A good statement of the minimalist view. I don't believe it, because I don't believe that truth is confined to language. An uneasy feeling I can't put into words can turn out to be true. Truth is a relational feature of mental states. |
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) |
4752 | Deflationism must reduce bivalence ('p is true or false') to excluded middle ('p or not-p') [Engel] |
Full Idea: It is said that deflationism cannot even formulate the principle of bivalence, for 'either p is true or p is false' will amount to the principle of excluded middle, 'either p or not-p'. | |
From: Pascal Engel (Truth [2002], §2.4) | |
A reaction: Presumably deflationists don't lost any sleep over this - in fact, it looks like a good concise way to state the deflationist thesis. However, excluded middle refers to a proposition (not-p) that was never mentioned by bivalence. Cf Idea 6163. |
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. |
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. |
4762 | The Humean theory of motivation is that beliefs may be motivators as well as desires [Engel] |
Full Idea: A problem for the Humean theory of motivation is that it is disputed that beliefs are only representational states, which cannot, unlike desires, move us to act. | |
From: Pascal Engel (Truth [2002], §4.2) | |
A reaction: This is a crucial issue for Humeans and empiricists. Rationalists claim that people act for reasons, so that reasons are intrinsically motivational (like the Form of the Good), and reasons may even be considered direct causes of actions. |
4754 | Our beliefs are meant to fit the world (i.e. be true), where we want the world to fit our desires [Engel] |
Full Idea: Belief is said to 'aim at truth', in the sense that beliefs are the kind of mental states that have to be true for the mind to 'fit' the world (where our desires have the opposite 'direction of fit'; the world is supposed to fit our desires). | |
From: Pascal Engel (Truth [2002], §2.5) | |
A reaction: I don't think it is possible to give a plausible definition of belief without mentioning truth. Hume's account of them as thoughts with a funny feeling attached is ridiculous. Thinking is an activity, not a passive state. |
4763 | 'Evidentialists' say, and 'voluntarists' deny, that we only believe on the basis of evidence [Engel] |
Full Idea: The 'evidentialists' (such as Locke and Hume) deny, and the 'voluntarists' (such as William James) affirm, that we ought to, or at least may, believe for other reasons than evidential epistemic reasons (e.g. for pragmatic reasons). | |
From: Pascal Engel (Truth [2002], §5.2) | |
A reaction: No need to be black-or-white here. Blatant evidence compels belief, but we may also come to believe by spotting a coherence, without additional evidence. We can also be in a state of trying to believe something. But see 4764. |
4746 | Pragmatism is better understood as a theory of belief than as a theory of truth [Engel] |
Full Idea: Pragmatism in general is better construed as a certain conception of belief, rather than as a distinctive conception of truth. | |
From: Pascal Engel (Truth [2002], §1.5) | |
A reaction: Which is why aspiring relativists drift towards the pragmatic theory - because they want to dispense with truth (and hence knowledge), and put mere belief in its place. |
4764 | We cannot directly control our beliefs, but we can control the causes of our involuntary beliefs [Engel] |
Full Idea: Direct psychological voluntarism about beliefs seems to be false, but we can have an indirect voluntary control on many of our beliefs, by manipulating the states in us that are involuntary and which lead to certain beliefs. | |
From: Pascal Engel (Truth [2002], §5.2) | |
A reaction: Very nice! This points two ways - to scientific experiments, which can have compelling outcomes (see Fodor), and to brain-washing, and especially auto-brainwashing (only reading articles which support your favourites theories). What magazines do you take? |
4759 | Mental states as functions are second-order properties, realised by first-order physical properties [Engel] |
Full Idea: For functionalism mental states as roles are second-order properties that have to be realised in various ways in first-order physical properties. | |
From: Pascal Engel (Truth [2002], §3.3) | |
A reaction: I take that to be properties-of-properties, as in 'bright red' or 'poignantly beautiful'. I am inclined to think (with Edelman) that mind is a process, not a property. |
6386 | In no important way can psychology be reduced to the physical sciences [Davidson] |
Full Idea: There is no important sense in which psychology can be reduced to the physical sciences. | |
From: Donald Davidson (The Material Mind [1973], p.259) | |
A reaction: In no 'important' way can the beauty of the Lake District be reduced to geology - but it is geology. 'Important' to whom? To a metaphysician, I would say psychology does reduce to physics, and that is important, but it is not important to a psychologist. |