19 ideas
| 12129 | 'Truth' may only apply within a theory [Kuhn] |
| Full Idea: 'Truth' may, like 'proof', be a term with only intra-theoretic applications. | |
| From: Thomas S. Kuhn (Reflections on my Critics [1970], §5) | |
| A reaction: I think we can blame Tarski (via Quine, Kuhn's teacher) for this one. I take it to be an utter failure to grasp the meaning of the word 'truth' (and sneakily substituting 'satisfaction' for it). For a start, we have to compare theories on some basis. |
| 16014 | It is controversial whether only 'numerical identity' allows two things to be counted as one [Noonan] |
| Full Idea: 'Numerical identity' implies the controversial view that it is the only identity relation in accordance with which we can properly count (or number) things: x and y are to be properly counted as one just in case they are numerically identical. | |
| From: Harold Noonan (Identity [2009], §1) | |
| A reaction: Noonan cites Geach, presumably to remind us of relative identity, where two things may be one or two, depending on what they are relative to. The one 'guard on the gate' may actually be two men. |
| 16024 | I could have died at five, but the summation of my adult stages could not [Noonan] |
| Full Idea: Persons have different modal properties from the summations of person-stages. …I might have died when I was five. But the maximal summation of person-stages which perdurantists say is me could not have had a temporal extent of a mere five years. | |
| From: Harold Noonan (Identity [2009], §5) | |
| A reaction: Thus the summation of stages seems to fail Leibniz's Law, since truths about a part are not true of the whole. But my foot might be amputated without me being amputated. The objection is the fallacy of composition? |
| 16023 | Stage theorists accept four-dimensionalism, but call each stage a whole object [Noonan] |
| Full Idea: Stage theorists, accepting the ontology of perdurance, modify the semantics to secure the result that fatness is a property of a cat. Every temporal part of a cat (such as Tabby-on-Monday) is a cat. …(but they pay a price over the counting of cats). | |
| From: Harold Noonan (Identity [2009], §5) | |
| A reaction: [Noonan cites Hawley and Sider for this view. The final parenthesis compresses Noonan] I would take the difficulty over counting cats to be fatal to the view. It produces too many cats, or too few, or denies counting altogether. |
| 16015 | Problems about identity can't even be formulated without the concept of identity [Noonan] |
| Full Idea: If identity is problematic, it is difficult to see how the problem could be resolved, since it is difficult to see how a thinker could have the conceptual resources with which to explain the concept of identity whilst lacking that concept itself. | |
| From: Harold Noonan (Identity [2009], §1) | |
| A reaction: I don't think I accept this. We can comprehend the idea of a mind that didn't think in terms of identities (at least for objects). I suppose any relation of a mind to the world has to distinguish things in some way. Does the Parmenidean One have identity? |
| 16017 | Identity is usually defined as the equivalence relation satisfying Leibniz's Law [Noonan] |
| Full Idea: Numerical identity is usually defined as the equivalence relation (or: the reflexive relation) satisfying Leibniz's Law, the indiscernibility of identicals, where everything true of x is true of y. | |
| From: Harold Noonan (Identity [2009], §2) | |
| A reaction: Noonan says this must include 'is identical to x' among the truths, and so is circular |
| 16016 | Identity definitions (such as self-identity, or the smallest equivalence relation) are usually circular [Noonan] |
| Full Idea: Identity can be circularly defined, as 'the relation everything has to itself and to nothing else', …or as 'the smallest equivalence relation'. | |
| From: Harold Noonan (Identity [2009], §2) | |
| A reaction: The first one is circular because 'nothing else' implies identity. The second is circular because it has to quantify over all equivalence relations. (So says Noonan). |
| 16020 | Identity can only be characterised in a second-order language [Noonan] |
| Full Idea: There is no condition in a first-order language for a predicate to express identity, rather than indiscernibility within the resources of the language. Leibniz's Law is statable in a second-order language, so identity can be uniquely characterised. | |
| From: Harold Noonan (Identity [2009], §2) | |
| A reaction: The point is that first-order languages only refer to all objects, but you need to refer to all properties to include Leibniz's Law. Quine's 'Identity, Ostension and Hypostasis' is the source of this idea. |
| 16018 | Indiscernibility is basic to our understanding of identity and distinctness [Noonan] |
| Full Idea: Leibniz's Law (the indiscernibility of identicals) appears to be crucial to our understanding of identity, and, more particularly, to our understanding of distinctness. | |
| From: Harold Noonan (Identity [2009], §2) | |
| A reaction: True, but indiscernibility concerns the epistemology, and identity concerns the ontology. |
| 16019 | Leibniz's Law must be kept separate from the substitutivity principle [Noonan] |
| Full Idea: Leibniz's Law must be clearly distinguished from the substitutivity principle, that if 'a' and 'b' are codesignators they are substitutable salva veritate. | |
| From: Harold Noonan (Identity [2009], §2) | |
| A reaction: He gives a bunch of well-known problem cases for substitutivity. The Morning Star, Giorgione, and the number of planets won't work. Belief contexts, or facts about spelling, may not be substitutable. |
| 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 |
| 18076 | Most theories are continually falsified [Kuhn, by Kitcher] |
| Full Idea: Kuhn contends that almost all theories are falsified at almost all times. | |
| From: report of Thomas S. Kuhn (Structure of Scientific Revolutions (2nd ed) [1962]) by Philip Kitcher - The Nature of Mathematical Knowledge 07.1 | |
| A reaction: This is obviously meant to demolish Karl Popper. |
| 22191 | Kuhn's scientists don't aim to falsifying their paradigm, because that is what they rely on [Kuhn, by Gorham] |
| Full Idea: In Kuhn's view scientists are decidedly not interested in falsifying their paradigm, because without a paradigm there is no systematic inquiry at all. | |
| From: report of Thomas S. Kuhn (Structure of Scientific Revolutions (2nd ed) [1962]) by Geoffrey Gorham - Philosophy of Science 3 | |
| A reaction: This seems to be one of the stronger aspects of Kuhn's account. You'd be leaving the big house, to go out on the road with a tent. |
| 6809 | Kuhn came to accept that all scientists agree on a particular set of values [Kuhn, by Bird] |
| Full Idea: Kuhn later came to accept that there are five values to which scientists in all paradigms adhere: accuracy; consistency with accepted theories; broad scope; simplicity; and fruitfulness. | |
| From: report of Thomas S. Kuhn (Reflections on my Critics [1970]) by Alexander Bird - Philosophy of Science Ch.8 | |
| A reaction: To shake off the relativism for which Kuhn is notorious, we should begin by asking the question WHY scientists favoured these particular values, rather than (say) bizarreness, consistency with Lewis Carroll, or alliteration. (They are epistemic virtues). |
| 22183 | Switching scientific paradigms is a conversion experience [Kuhn] |
| Full Idea: The transfer of allegiance from paradigm to paradigm is a conversion experience which cannot be forced. | |
| From: Thomas S. Kuhn (Structure of Scientific Revolutions (2nd ed) [1962]), quoted by Samir Okasha - Philosophy of Science: Very Short Intro (2nd ed) 5 | |
| A reaction: This is the controversial part of Kuhn, which says that the most important decisions are not really rational. Anyone who thought the interpretation of a bunch of evidence is logical needed their head examined. But it IS rational. |
| 6162 | Kuhn has a description theory of reference, so the reference of 'electron' changes with the descriptions [Rowlands on Kuhn] |
| Full Idea: Kuhn and Feyerabend adopt a description theory of reference; the term 'electron' refers to whatever satisfies the descriptions associated with electrons, and since these descriptions vary between theories, so too must the reference. | |
| From: comment on Thomas S. Kuhn (Structure of Scientific Revolutions (2nd ed) [1962]) by Mark Rowlands - Externalism Ch.3 | |
| A reaction: This is a key idea in modern philosophy, showing why all of reality and science were at stake when Kripke and others introduced a causal theory of reference. All the current debates about externalism and essentialism grow from this problem. |
| 22184 | Incommensurability assumes concepts get their meaning from within the theory [Kuhn, by Okasha] |
| Full Idea: The doctrine of incommensurability stems from Kuhn's belief that scientific concepts derive their meaning from the theory in which they play a role. | |
| From: report of Thomas S. Kuhn (Structure of Scientific Revolutions (2nd ed) [1962]) by Samir Okasha - Philosophy of Science: Very Short Intro (2nd ed) 5 | |
| A reaction: Quine was the source of this. Kripke's direct reference theory was meant to be the answer. |
| 7619 | Galileo's notions can't be 'incommensurable' if we can fully describe them [Putnam on Kuhn] |
| Full Idea: To tell us that Galileo had 'incommensurable' notions and then go on to describe them at length is totally incoherent. | |
| From: comment on Thomas S. Kuhn (Structure of Scientific Revolutions (2nd ed) [1962]) by Hilary Putnam - Reason, Truth and History Ch.5 | |
| A reaction: How refreshingly sensible. Incommensurability is the sort of nonsense you slide into if you take an instrumental view of science. But scientists are continually aim to pin down what is actually there. Translation between theories is very difficult! |
| 12128 | In theory change, words shift their natural reference, so the theories are incommensurable [Kuhn] |
| Full Idea: In transitions between theories words change their meanings or applicability. Though most of the signs are used before and after a revolution - force, mass, cell - the ways they attach to nature has changed. Successive theories are thus incommensurable. | |
| From: Thomas S. Kuhn (Reflections on my Critics [1970], §6) | |
| A reaction: A very nice statement of the view, from the horse's mouth. A great deal of recent philosophy has been implicitly concerned with meeting Kuhn's challenge, by providing an account of reference that doesn't have such problems. |