21 ideas
| 3798 | An overexamined life is as bad as an unexamined one [Dennett] |
| Full Idea: The unexamined life may not be worth living, but the overexamined life is nothing to write home about either. | |
| From: Daniel C. Dennett (Elbow Room: varieties of free will [1984], §4.2) | |
| A reaction: Presumably he means a life which is all theory and no practice. Compare Idea 343. |
| 3801 | Rationality requires the assumption that things are either for better or worse [Dennett] |
| Full Idea: We must assume that something matters - that some things are for better and some things are for worse, for without that our assumed rationality would have nothing on which to get a purchase. | |
| From: Daniel C. Dennett (Elbow Room: varieties of free will [1984], §7.1) | |
| A reaction: It does seem that rationality wouldn't exist as an activity without some value to motivate it. |
| 19125 | If we define truth, we can eliminate it [Halbach/Leigh] |
| Full Idea: If truth can be explicitly defined, it can be eliminated. | |
| From: Halbach,V/Leigh,G.E. (Axiomatic Theories of Truth (2013 ver) [2013], 1.3) | |
| A reaction: That we could just say p corresponds to the facts, or p coheres with our accepted beliefs, or p is the aim of our enquiries, and never mention the word 'true'. Definition is a strategy for reduction or elimination. |
| 19128 | If a language cannot name all objects, then satisfaction must be used, instead of unary truth [Halbach/Leigh] |
| Full Idea: If axioms are formulated for a language (such as set theory) that lacks names for all objects, then they require the use of a satisfaction relation rather than a unary truth predicate. | |
| From: Halbach,V/Leigh,G.E. (Axiomatic Theories of Truth (2013 ver) [2013], 3.3) | |
| A reaction: I take it this is an important idea for understanding why Tarski developed his account of truth based on satisfaction. |
| 19120 | Semantic theories need a powerful metalanguage, typically including set theory [Halbach/Leigh] |
| Full Idea: Semantic approaches to truth usually necessitate the use of a metalanguage that is more powerful than the object-language for which it provides a semantics. It is usually taken to include set theory. | |
| From: Halbach,V/Leigh,G.E. (Axiomatic Theories of Truth (2013 ver) [2013], 1) | |
| A reaction: This is a motivation for developing an axiomatic account of truth, that moves it into the object language. |
| 19127 | The T-sentences are deductively weak, and also not deductively conservative [Halbach/Leigh] |
| Full Idea: Although the theory is materially adequate, Tarski thought that the T-sentences are deductively too weak. …Also it seems that the T-sentences are not conservative, because they prove in PA that 0=0 and ¬0=0 are different, so at least two objects exist. | |
| From: Halbach,V/Leigh,G.E. (Axiomatic Theories of Truth (2013 ver) [2013], 3.2) | |
| A reaction: They are weak because they can't prove completeness. This idea give two reasons for looking for a better theory of truth. |
| 19124 | A natural theory of truth plays the role of reflection principles, establishing arithmetic's soundness [Halbach/Leigh] |
| Full Idea: If a natural theory of truth is added to Peano Arithmetic, it is not necessary to add explicity global reflection principles to assert soundness, as the truth theory proves them. Truth theories thus prove soundess, and allows its expression. | |
| From: Halbach,V/Leigh,G.E. (Axiomatic Theories of Truth (2013 ver) [2013], 1.2) | |
| A reaction: This seems like a big attraction of axiomatic theories of truth for students of metamathematics. |
| 19126 | If deflationary truth is not explanatory, truth axioms should be 'conservative', proving nothing new [Halbach/Leigh] |
| Full Idea: If truth does not have any explanatory force, as some deflationists claim, the axioms of truth should not allow us to prove any new theorems that do not involve the truth predicate. That is, a deflationary axiomatisation of truth should be 'conservative'. | |
| From: Halbach,V/Leigh,G.E. (Axiomatic Theories of Truth (2013 ver) [2013], 1.3) | |
| A reaction: So does truth have 'explanatory force'? These guys are interested in explaining theorems of arithmetic, but I'm more interested in real life. People do daft things because they have daft beliefs. Logic should be neutral, but truth has values? |
| 19129 | The FS axioms use classical logical, but are not fully consistent [Halbach/Leigh] |
| Full Idea: It is a virtue of the Friedman-Sheard axiomatisation that it is thoroughly classical in its logic. Its drawback is that it is ω-inconsistent. That is, it proves &exists;x¬φ(x), but proves also φ(0), φ(1), φ(2), … | |
| From: Halbach,V/Leigh,G.E. (Axiomatic Theories of Truth (2013 ver) [2013], 4.3) | |
| A reaction: It seems the theory is complete (and presumably sound), yet not fully consistent. FS also proves the finite levels of Tarski's hierarchy, but not the transfinite levels. |
| 19130 | KF is formulated in classical logic, but describes non-classical truth, which allows truth-value gluts [Halbach/Leigh] |
| Full Idea: KF is formulated in classical logic, but describes a non-classical notion of truth. It allow truth-value gluts, making some sentences (such as the Liar) both true and not-true. Some authors add an axiom ruling out such gluts. | |
| From: Halbach,V/Leigh,G.E. (Axiomatic Theories of Truth (2013 ver) [2013], 4.4) | |
| A reaction: [summary, which I hope is correct! Stanford is not wholly clear] |
| 19121 | We can reduce properties to true formulas [Halbach/Leigh] |
| Full Idea: One might say that 'x is a poor philosopher' is true of Tom instead of saying that Tom has the property of being a poor philosopher. We quantify over formulas instead of over definable properties, and thus reduce properties to truth. | |
| From: Halbach,V/Leigh,G.E. (Axiomatic Theories of Truth (2013 ver) [2013], 1.1) | |
| A reaction: [compressed] This stuff is difficult (because the axioms are complex and hard to compare), but I am excited (yes!) about this idea. Their point is that you need a truth predicate within the object language for this, which disquotational truth forbids. |
| 19122 | Nominalists can reduce theories of properties or sets to harmless axiomatic truth theories [Halbach/Leigh] |
| Full Idea: The reduction of second-order theories (of properties or sets) to axiomatic theories of truth is a form of reductive nominalism, replacing existence assumptions (e.g. comprehension axioms) by innocuous assumptions about the truth predicate. | |
| From: Halbach,V/Leigh,G.E. (Axiomatic Theories of Truth (2013 ver) [2013], 1.1) | |
| A reaction: I'm currently thinking that axiomatic theories of truth are the most exciting development in contemporary philosophy. See Halbach and Horsten. |
| 3802 | Why pronounce impossible what you cannot imagine? [Dennett] |
| Full Idea: You say you cannot imagine that p, and therefore declare that p is impossible. Mightn't that be hubris? | |
| From: Daniel C. Dennett (Elbow Room: varieties of free will [1984], §7.3) |
| 3795 | Causal theories require the "right" sort of link (usually unspecified) [Dennett] |
| Full Idea: In causal theories of knowledge and reference, the causal chain between object and thought must be of the "right" sort - the nature of rightness to be specified later, typically. | |
| From: Daniel C. Dennett (Elbow Room: varieties of free will [1984], §3.3 n14) | |
| A reaction: This is now the standard objection to a purely causal account of reference. Which of the many causal chains causes the meaning? Knowledge of maths is a further problem for it. |
| 3797 | I am the sum total of what I directly control [Dennett] |
| Full Idea: Control is the ultimate criterion of the self: I am the sum total of the parts I control directly. | |
| From: Daniel C. Dennett (Elbow Room: varieties of free will [1984], §4.2) | |
| A reaction: This looks awfully like a flagrant self-contradiction, and I think it is. It seems pretty obvious that there is at least a distinction between the bit or bits that do the controlling, and the bits that get controlled. |
| 3800 | You can be free even though force would have prevented you doing otherwise [Dennett, by PG] |
| Full Idea: If a brain implant would compel you to perform an action which you in fact freely choose, then you are free, but couldn't have done otherwise. | |
| From: report of Daniel C. Dennett (Elbow Room: varieties of free will [1984], §6.1) by PG - Db (ideas) |
| 3803 | Can we conceive of a being with a will freer than our own? [Dennett] |
| Full Idea: Can I even conceive of beings whose wills are freer than our own? | |
| From: Daniel C. Dennett (Elbow Room: varieties of free will [1984], §7.3) |
| 3791 | Awareness of thought is a step beyond awareness of the world [Dennett] |
| Full Idea: The creature who is not only sensitive to patterns in its environment, but also sensitive to patterns in its own reactions to patterns in its environment, has taken a major step. | |
| From: Daniel C. Dennett (Elbow Room: varieties of free will [1984], §2.2) |
| 3794 | Foreknowledge permits control [Dennett] |
| Full Idea: Foreknowledge is what permits control. | |
| From: Daniel C. Dennett (Elbow Room: varieties of free will [1984], §3.2) |
| 3796 | The active self is a fiction created because we are ignorant of our motivations [Dennett] |
| Full Idea: Faced with our inability to 'see' where the centre or source of our free actions is,…we exploit the gaps in our self-knowledge by filling it with a mysterious entity, the unmoved mover, the active self. | |
| From: Daniel C. Dennett (Elbow Room: varieties of free will [1984], §4.1) | |
| A reaction: I am convinced that there is no such things as free will; its origins are to be found in religion, where it is a necessary feature of a very supreme God. I don't believe for a moment that we need to believe in free will. |
| 7903 | The six perfections are giving, morality, patience, vigour, meditation, and wisdom [Nagarjuna] |
| Full Idea: The six perfections are of giving, morality, patience, vigour, meditation, and wisdom. | |
| From: Nagarjuna (Mahaprajnaparamitashastra [c.120], 88) | |
| A reaction: What is 'morality', if giving is not part of it? I like patience and vigour being two of the virtues, which immediately implies an Aristotelian mean (which is always what is 'appropriate'). |