19 ideas
| 17486 | Supervenience is simply modally robust property co-variance [Hendry] |
| Full Idea: Supervenience is not an ontological relationship, being just modally robust property co-variance. | |
| From: Robin F. Hendry (Chemistry [2008], 'Ontol') | |
| A reaction: I take supervenience to be nothing more than an interesting phenomenon that requires explanation. I suppose Humean Supervenience is a priori metaphysics, since you could hardly explain it. |
| 19718 | Indefeasibility does not imply infallibility [Grundmann] |
| Full Idea: Infallibility does not follow from indefeasibility. | |
| From: Thomas Grundmann (Defeasibility Theory [2011], 'Significance') | |
| A reaction: If very little evidence exists then this could clearly be the case. It is especially true of historical and archaeological evidence. |
| 19717 | Can a defeater itself be defeated? [Grundmann] |
| Full Idea: Can the original justification of a belief be regained through a successful defeat of a defeater? | |
| From: Thomas Grundmann (Defeasibility Theory [2011], 'Defeater-Defs') | |
| A reaction: [Jäger 2005 addresses this] I would have thought the answer is yes. I aspire to coherent justifications, so I don't see justifications as a chain of defeat and counter-defeat, but as collective groups of support and challenge. |
| 19716 | Simple reliabilism can't cope with defeaters of reliably produced beliefs [Grundmann] |
| Full Idea: An unmodified reliabilism does not accommodate defeaters, and surely there can be defeaters against reliably produced beliefs? | |
| From: Thomas Grundmann (Defeasibility Theory [2011], 'Defeaters') | |
| A reaction: [He cites Bonjour 1980] Reliabilism has plenty of problems anyway, since a generally reliable process can obviously occasionally produce a bad result. 20:20 vision is not perfect vision. Internalist seem to like defeaters. |
| 19715 | You can 'rebut' previous beliefs, 'undercut' the power of evidence, or 'reason-defeat' the truth [Grundmann] |
| Full Idea: There are 'rebutting' defeaters against the truth of a previously justified belief, 'undercutting' defeaters against the power of the evidence, and 'reason-defeating' defeaters against the truth of the reason for the belief. | |
| From: Thomas Grundmann (Defeasibility Theory [2011], 'How') | |
| A reaction: That is (I think) that you can defeat the background, the likelihood, or the truth. He cites Pollock 1986, and implies that these are standard distinctions about defeaters. |
| 19713 | Defeasibility theory needs to exclude defeaters which are true but misleading [Grundmann] |
| Full Idea: Advocates of the defeasibility theory have tried to exclude true pieces of information that are misleading defeaters. | |
| From: Thomas Grundmann (Defeasibility Theory [2011], 'What') | |
| A reaction: He gives as an example the genuine news of a claim that the suspect has a twin. |
| 19714 | Knowledge requires that there are no facts which would defeat its justification [Grundmann] |
| Full Idea: The 'defeasibility theory' of knowledge claims that knowledge is only present if there are no facts that - if they were known - would be genuine defeaters of the relevant justification. | |
| From: Thomas Grundmann (Defeasibility Theory [2011], 'What') | |
| A reaction: Something not right here. A genuine defeater would ensure the proposition was false, so it would simply fail the truth test. So we need a 'defeater' for a truth, which must therefore by definition be misleading. Many qualifications have to be invoked. |
| 19719 | 'Moderate' foundationalism has basic justification which is defeasible [Grundmann] |
| Full Idea: Theories that combine basic justification with the defeasibility of this justification are referred to as 'moderate' foundationalism. | |
| From: Thomas Grundmann (Defeasibility Theory [2011], 'Significance') | |
| A reaction: I could be more sympathetic to this sort of foundationalism. But it begins to sound more like Neurath's boat (see Quine) than like Descartes' metaphor of building foundations. |
| 20653 | Six reduction levels: groups, lives, cells, molecules, atoms, particles [Putnam/Oppenheim, by Watson] |
| Full Idea: There are six 'reductive levels' in science: social groups, (multicellular) living things, cells, molecules, atoms, and elementary particles. | |
| From: report of H.Putnam/P.Oppenheim (Unity of Science as a Working Hypothesis [1958]) by Peter Watson - Convergence 10 'Intro' | |
| A reaction: I have the impression that fields are seen as more fundamental that elementary particles. What is the status of the 'laws' that are supposed to govern these things? What is the status of space and time within this picture? |
| 17481 | Nuclear charge (plus laws) explains electron structure and spectrum, but not vice versa [Hendry] |
| Full Idea: Given relevant laws of nature (quantum mechanics, the exclusion principle) nuclear charge determines and explains electronic structure and spectroscopic behaviour, but not vice versa. | |
| From: Robin F. Hendry (Chemistry [2008], 'Micro') | |
| A reaction: I argue that the first necessary condition for essentialism is a direction of explanation, and here we seem to have one. |
| 17478 | Maybe two kinds are the same if there is no change of entropy on isothermal mixing [Hendry] |
| Full Idea: One suggestion is that any two different substance, however alike, exhibit a positive entropy change on mixing. So absence of entropy change on isothermal mixing provides a criterion of sameness of kind. | |
| From: Robin F. Hendry (Chemistry [2008], 'Micro') | |
| A reaction: [He cites Paul Needham 2000] This sounds nice, because at a more amateur level we can say that stuff is the same if mixing two samples of it produces no difference. I call it the Upanishads Test. |
| 17479 | The nature of an element must survive chemical change, so it is the nucleus, not the electrons [Hendry] |
| Full Idea: Whatever earns something membership of the extension of 'krypton' must be a property that can survive chemical change and, therefore, the gain and loss of electrons. Hence what makes it krypton must be a nuclear property. | |
| From: Robin F. Hendry (Chemistry [2008], 'Micro') | |
| A reaction: A very nice illuminating example of essentialism in chemistry. The 'nature' is what survives through change, just like what Aristotle said, innit? |
| 17485 | Maybe water is the smallest part of it that still counts as water (which is H2O molecules) [Hendry] |
| Full Idea: If they do count as water, individual H2O molecules are the smallest items that can qualify as water on their own account. Hydroxyl ions and protons, in contrast, qualify as water only as part of a larger body. | |
| From: Robin F. Hendry (Chemistry [2008], 'Micro') | |
| A reaction: As Aristotle might say, this is the homoeomerous aspect of water. This is Hendry's own proposal, and seems rather good. |
| 17484 | Maybe the nature of water is macroscopic, and not in the microstructure [Hendry] |
| Full Idea: Some deny that that microstructure is what makes it water; substance identity and difference should be determined instead by macroscopic similarities and differences. | |
| From: Robin F. Hendry (Chemistry [2008], 'Micro') | |
| A reaction: Very plausible. Is the essential nature of human beings to be found in the structure of our cells? |
| 17482 | Compounds can differ with the same collection of atoms, so structure matters too [Hendry] |
| Full Idea: The distinctness of the isomers ethanol (CH3CH2OH, boiling at 78.4°) and dimethyl ether (CH3OCH3, boiling at -24.9°) must lie in their different molecular structures. ...But structure has continuously varying quantities, like bond length and angle. | |
| From: Robin F. Hendry (Chemistry [2008], 'Micro') | |
| A reaction: [compressed] This seems to imply that what matters is an idealised abstraction of the structure (i.e. its topology), which is a reason for denying that chemistry is reducible to mere physics. |
| 17483 | Water continuously changes, with new groupings of molecules [Hendry] |
| Full Idea: Macroscopic bodies of water are complex and dynamic congeries of different molecular species, in which there is a constant dissociation of individual molecules, re-association of ions, and formation, growth and disassociation of oligomers. | |
| From: Robin F. Hendry (Chemistry [2008], 'Micro') | |
| A reaction: The point is that these activities are needed to explain the behaviour of water (such as its conductivity). |
| 17476 | Elements survive chemical change, and are tracked to explain direction and properties [Hendry] |
| Full Idea: Elements survive chemical change, and chemical explanations track them from one composite substance to another, thereby explaining both the direction of the chemical change, and the properties of the substances they compose. | |
| From: Robin F. Hendry (Chemistry [2008], Intro) | |
| A reaction: [The 16,000th idea of this database, entered on Guy Fawkes' Day 2013] |
| 17477 | Defining elements by atomic number allowed atoms of an element to have different masses [Hendry] |
| Full Idea: In 1923 elements were defined as populations of atoms with the same nuclear charge (i.e. atomic number), allowing that atoms of the same element may have different masses. | |
| From: Robin F. Hendry (Chemistry [2008], 'Chem') | |
| A reaction: The point is that it allowed isotopes of the same element to come under one heading. This is fine for the heavier elements, but a bit dubious for the very light ones (where an isotope makes a bigger difference). |
| 17480 | Generally it is nuclear charge (not nuclear mass) which determines behaviour [Hendry] |
| Full Idea: In general, nuclear charge is the overwhelming determinant of an element's chemical behaviour, while nuclear mass is a negligible factor. | |
| From: Robin F. Hendry (Chemistry [2008], 'Micro') | |
| A reaction: The exception is the isotopes of very light elements light hydrogen. |