19 ideas
| 12772 | Philosophy is a value- and attitude-driven enterprise [Fraassen] |
| Full Idea: Philosophy is a value- and attitude-driven enterprise; philosophy is in false consciousness when it sees itself otherwise. | |
| From: Bas C. van Fraassen (The Empirical Stance [2002], 1.5) | |
| A reaction: It is one thing to be permeated with values, and another to be value-driven. Truth, reason and logic are (I take it) granted a high value in philosophy, just as the offside rule is in football. I am trying to place reality in charge, not humanity. |
| 12771 | Is it likely that a successful, coherent, explanatory ontological hypothesis is true? [Fraassen] |
| Full Idea: How likely is it that a truly successful, coherent, explanatory ontological hypothesis is true? | |
| From: Bas C. van Fraassen (The Empirical Stance [2002], 1.5) | |
| A reaction: Van Fraassen announces "I reject metaphysic" (p.3), so we know where he stands. Anything becomes less certain as it moves to a higher level of generality. Should we abandon generalisation? There is much illumination in metaphysics. |
| 12773 | Analytic philosophy has an exceptional arsenal of critical tools [Fraassen] |
| Full Idea: Analytical philosophy can rightly pride itself on having produced the greatest critical arsenal the world has ever known. | |
| From: Bas C. van Fraassen (The Empirical Stance [2002], 1.6) | |
| A reaction: This is, of course, in the context of a scathing attack on the desire to use analytical methods to do speculative metaphysics. I say that if these are the best tools, then we should push forward with them to see how far we can get. |
| 12770 | We may end up with a huge theory of carefully constructed falsehoods [Fraassen] |
| Full Idea: The specter that faces us is that we may end up having explained all that is dreamt of in our philosophies by intricately crafted postulates that are false. | |
| From: Bas C. van Fraassen (The Empirical Stance [2002], 1.5) | |
| A reaction: This is more persuasive that Idea 12769. People who cannot bear to live with a total absence of explanation (with Keats's 'negative capability') are most in danger from this threat. |
| 10301 | The axiom of choice is controversial, but it could be replaced [Shapiro] |
| Full Idea: The axiom of choice has a troubled history, but is now standard in mathematics. It could be replaced with a principle of comprehension for functions), or one could omit the variables ranging over functions. | |
| From: Stewart Shapiro (Higher-Order Logic [2001], n 3) |
| 10588 | First-order logic is Complete, and Compact, with the Löwenheim-Skolem Theorems [Shapiro] |
| Full Idea: Early study of first-order logic revealed a number of important features. Gödel showed that there is a complete, sound and effective deductive system. It follows that it is Compact, and there are also the downward and upward Löwenheim-Skolem Theorems. | |
| From: Stewart Shapiro (Higher-Order Logic [2001], 2.1) |
| 10298 | Some say that second-order logic is mathematics, not logic [Shapiro] |
| Full Idea: Some authors argue that second-order logic (with standard semantics) is not logic at all, but is a rather obscure form of mathematics. | |
| From: Stewart Shapiro (Higher-Order Logic [2001], 2.4) |
| 10299 | If the aim of logic is to codify inferences, second-order logic is useless [Shapiro] |
| Full Idea: If the goal of logical study is to present a canon of inference, a calculus which codifies correct inference patterns, then second-order logic is a non-starter. | |
| From: Stewart Shapiro (Higher-Order Logic [2001], 2.4) | |
| A reaction: This seems to be because it is not 'complete'. However, moves like plural quantification seem aimed at capturing ordinary language inferences, so the difficulty is only that there isn't a precise 'calculus'. |
| 10300 | Logical consequence can be defined in terms of the logical terminology [Shapiro] |
| Full Idea: Informally, logical consequence is sometimes defined in terms of the meanings of a certain collection of terms, the so-called 'logical terminology'. | |
| From: Stewart Shapiro (Higher-Order Logic [2001], 2.4) | |
| A reaction: This seems to be a compositional account, where we build a full account from an account of the atomic bits, perhaps presented as truth-tables. |
| 10290 | Second-order variables also range over properties, sets, relations or functions [Shapiro] |
| Full Idea: Second-order variables can range over properties, sets, or relations on the items in the domain-of-discourse, or over functions from the domain itself. | |
| From: Stewart Shapiro (Higher-Order Logic [2001], 2.1) |
| 10590 | Up Löwenheim-Skolem: if natural numbers satisfy wffs, then an infinite domain satisfies them [Shapiro] |
| Full Idea: Upward Löwenheim-Skolem: if a set of first-order formulas is satisfied by a domain of at least the natural numbers, then it is satisfied by a model of at least some infinite cardinal. | |
| From: Stewart Shapiro (Higher-Order Logic [2001], 2.1) |
| 10296 | The Löwenheim-Skolem Theorems fail for second-order languages with standard semantics [Shapiro] |
| Full Idea: Both of the Löwenheim-Skolem Theorems fail for second-order languages with a standard semantics | |
| From: Stewart Shapiro (Higher-Order Logic [2001], 2.3.2) |
| 10297 | The Löwenheim-Skolem theorem seems to be a defect of first-order logic [Shapiro] |
| Full Idea: The Löwenheim-Skolem theorem is usually taken as a sort of defect (often thought to be inevitable) of the first-order logic. | |
| From: Stewart Shapiro (Higher-Order Logic [2001], 2.4) | |
| A reaction: [He is quoting Wang 1974 p.154] |
| 10292 | Downward Löwenheim-Skolem: if there's an infinite model, there is a countable model [Shapiro] |
| Full Idea: Downward Löwenheim-Skolem: a finite or denumerable set of first-order formulas that is satisfied by a model whose domain is infinite is satisfied in a model whose domain is the natural numbers | |
| From: Stewart Shapiro (Higher-Order Logic [2001], 2.1) |
| 10294 | Second-order logic has the expressive power for mathematics, but an unworkable model theory [Shapiro] |
| Full Idea: Full second-order logic has all the expressive power needed to do mathematics, but has an unworkable model theory. | |
| From: Stewart Shapiro (Higher-Order Logic [2001], 2.1) | |
| A reaction: [he credits Cowles for this remark] Having an unworkable model theory sounds pretty serious to me, as I'm not inclined to be interested in languages which don't produce models of some sort. Surely models are the whole point? |
| 10591 | Logicians use 'property' and 'set' interchangeably, with little hanging on it [Shapiro] |
| Full Idea: In studying second-order logic one can think of relations and functions as extensional or intensional, or one can leave it open. Little turns on this here, and so words like 'property', 'class', and 'set' are used interchangeably. | |
| From: Stewart Shapiro (Higher-Order Logic [2001], 2.2.1) | |
| A reaction: Important. Students of the metaphysics of properties, who arrive with limited experience of logic, are bewildered by this attitude. Note that the metaphysics is left wide open, so never let logicians hijack the metaphysical problem of properties. |
| 1556 | By nature people are close to one another, but culture drives them apart [Hippias] |
| Full Idea: I regard you all as relatives - by nature, not by convention. By nature like is akin to like, but convention is a tyrant over humankind and often constrains people to act contrary to nature. | |
| From: Hippias (fragments/reports [c.430 BCE]), quoted by Plato - Protagoras 337c8 |
| 12769 | Inference to best explanation contains all sorts of hidden values [Fraassen] |
| Full Idea: The very phrase 'inference to the best explanation' should wave a red flag for us. What is good, better, best? What values are slipped in here, under a common name, and where do they come from? | |
| From: Bas C. van Fraassen (The Empirical Stance [2002], 1.5) | |
| A reaction: A point worth making, but overstated. If we are going to refuse to make judgements for fear that some wicked 'value' might creep in, our lives will be reduced to absurdity. |
| 12768 | We accept many scientific theories without endorsing them as true [Fraassen] |
| Full Idea: The choice among theories in science may be a choice to accept in some sense falling far short of endorsement as true. | |
| From: Bas C. van Fraassen (The Empirical Stance [2002], 1.5) | |
| A reaction: When put like this, it is hard to deny the force of Van Fraassen's reservations about science. Lots of people, including me, use scientific theories as working assumptions for life, with nothing like full confidence in their truth. |