112 ideas
| 12865 | Analytic philosophers may prefer formal systems because natural language is such mess [Simons] |
| Full Idea: The untidiness of natural language in its use of 'part' is perhaps one of the chief reasons why mereolologists have preferred to investigate formal systems with nice algebraic properties rather than get out and mix it with reality in all its messiness. | |
| From: Peter Simons (Parts [1987], 6.4) | |
| A reaction: [See Idea 12864 for the uses of 'part'] I am in the unhappy (and probably doomed) position of wanting to avoid both approaches. I try to operate as if the English language were transparent and we can just discuss the world. Very naïve. |
| 12815 | Classical mereology doesn't apply well to the objects around us [Simons] |
| Full Idea: The most fundamental criticism of classical mereology is that the theory is not applicable to most of the objects around us, and is accordingly of little use as a formal reconstruction of the concepts of part and whole which we actually employ. | |
| From: Peter Simons (Parts [1987], Intro) | |
| A reaction: This sounds splendidly dismissive, but one might compare it with possible worlds semantics for modal logic, which most people take with a pinch of salt as an actual commitment, but find wonderfully clarifying in modal reasoning. |
| 12819 | A 'part' has different meanings for individuals, classes, and masses [Simons] |
| Full Idea: It emerges that 'part', like other formal concepts, is not univocal, but has analogous meanings according to whether we talk of individuals, classes, or masses. | |
| From: Peter Simons (Parts [1987], Intro) | |
| A reaction: He suggests that unrestricted sums are appropriate for the last two, but not for individuals. There must be something univocal about the word - some awareness of a possible whole or larger entity to which the thing could belong. |
| 12832 | Complement: the rest of the Universe apart from some individual, written x-bar [Simons] |
| Full Idea: The 'complement' of each individual in mereology is the rest of the Universe outside it, that is U - x, but written as x-bar [x with a horizontal bar above it]. | |
| From: Peter Simons (Parts [1987], 1.1.10) | |
| A reaction: [Don't have a font for x-bar] See Idea 12831 for the 'Universe'. Simons suggest that the interest of this term is mainly historical and algebraic. |
| 12834 | Criticisms of mereology: parts? transitivity? sums? identity? four-dimensional? [Simons] |
| Full Idea: Main criticisms of mereology: we don't mean 'part' as improper; transitivity of 'part' is sometimes not transitive; no guarantee that there are 'sums'; the identity criteria for individuals are false; we are forced into materialistic four-dimensionalism. | |
| From: Peter Simons (Parts [1987], 3.2) | |
| A reaction: [Compressed summary; for four-dimensionalism see under 'Identity over Time'] Simons says these are in ascending order of importance. |
| 12827 | Difference: the difference of individuals is the remainder of an overlap, written 'x - y' [Simons] |
| Full Idea: The 'difference' of two individuals is the largest individual contained in x which has no part in common with y, expressed by 'x - y', read as 'the difference of x and y'. | |
| From: Peter Simons (Parts [1987], 1.1.07) |
| 12828 | General sum: the sum of objects satisfying some predicate, written σx(Fx) [Simons] |
| Full Idea: The 'general sum' of all objects satisfying a certain predicate is denoted by a variable-binding operator, expressed by 'σx(Fx)', read as 'the sum of objects satisfying F'. | |
| From: Peter Simons (Parts [1987], 1.1.08) | |
| A reaction: This, it seems, is introduced to restrict some infinite classes which aspire to be sums. |
| 12822 | Proper or improper part: x < y, 'x is (a) part of y' [Simons] |
| Full Idea: A 'proper or improper part' is expressed by 'x < y', read as 'x is (a) part of y'. The relatively minor deviation from normal usage (of including an improper part, i.e. the whole thing) is warranted by its algebraical convenience. | |
| From: Peter Simons (Parts [1987], 1.1.02) | |
| A reaction: Including an improper part (i.e. the whole thing) is not, Simons points out, uncontroversial, because the part being 'equal' to the whole is read as being 'identical' to the whole, which Simons is unwilling to accept. |
| 12823 | Overlap: two parts overlap iff they have a part in common, expressed as 'x o y' [Simons] |
| Full Idea: Two parts 'overlap' mereologically if and only if they have a part in common, expressed by 'x o y', read as 'x overlaps y'. Overlapping is reflexive and symmetric but not transitive. | |
| From: Peter Simons (Parts [1987], 1.1.03) | |
| A reaction: Simons points out that we are uncomfortable with overlapping (as in overlapping national boundaries), because we seem to like conceptual boundaries. We avoid overlap even in ordering primary colour terms, by having a no-man's-land. |
| 12824 | Disjoint: two individuals are disjoint iff they do not overlap, written 'x | y' [Simons] |
| Full Idea: Two individuals are 'disjoint' mereologically if and only if they do not overlap, expressed by 'x | y', read as 'x is disjoint from y'. Disjointedness is symmetric. | |
| From: Peter Simons (Parts [1987], 1.1.04) |
| 12825 | Product: the product of two individuals is the sum of all of their overlaps, written 'x · y' [Simons] |
| Full Idea: For two overlapping individuals their 'product' is the individual which is part of both and such that any common part of both is part of it, expressed by 'x · y', read as 'the product of x and y'. | |
| From: Peter Simons (Parts [1987], 1.1.05) | |
| A reaction: That is, the 'product' is the sum of any common parts between two individuals. In set theory all sets intersect at the null set, but mereology usually avoids the 'null individual'. |
| 12826 | Sum: the sum of individuals is what is overlapped if either of them are, written 'x + y' [Simons] |
| Full Idea: The 'sum' of two individuals is that individual which something overlaps iff it overlaps at least one of x and y, expressed by 'x + y', read as 'the sum of x and y'. It is central to classical extensional mereologies that any two individuals have a sum. | |
| From: Peter Simons (Parts [1987], 1.1.06) | |
| A reaction: This rather technical definition (defining an individual by the possibility of it being overlapped) does not always coincide with the smallest individual containing them both. |
| 12829 | General product: the nucleus of all objects satisfying a predicate, written πx(Fx) [Simons] |
| Full Idea: The 'general product' or 'nucleus' of all objects satisfying a certain predicate is denoted by a variable-binding operator, expressed by 'πx(Fx)', read as 'the product of objects satisfying F'. | |
| From: Peter Simons (Parts [1987], 1.1.08) | |
| A reaction: See Idea 12825 for 'product'. 'Nucleus' is a helpful word here. Thought: is the general product a candidate for a formal definition of essence? It would be a sortal essence - roughly, what all beetles have in common, just by being beetles. |
| 12830 | Universe: the mereological sum of all objects whatever, written 'U' [Simons] |
| Full Idea: The 'Universe' in mereology is the sum of all objects whatever, a unique individual of which all individuals are part. This is denoted by 'U'. Strictly, there can be no 'empty Universe', since the Universe is not a container, but the whole filling. | |
| From: Peter Simons (Parts [1987], 1.1.09) | |
| A reaction: This, of course, contrasts with set theory, which cannot have a set of all sets. At the lower end, set theory does have a null set, while mereology has no null individual. See David Lewis on combining the two theories. |
| 12831 | Atom: an individual with no proper parts, written 'At x' [Simons] |
| Full Idea: An 'atom' in mereology is an individual with no proper parts. We shall use the expression 'At x' to mean 'x is an atom'. | |
| From: Peter Simons (Parts [1987], 1.1.11) | |
| A reaction: Note that 'part' in standard mereology includes improper parts, so every object has at least one part, namely itself. |
| 12844 | Dissective: stuff is dissective if parts of the stuff are always the stuff [Simons] |
| Full Idea: Water is said not to be 'dissective', since there are parts of any quantity of water which are not water. | |
| From: Peter Simons (Parts [1987], 4.2) | |
| A reaction: This won't seem to do for any physical matter, but presumably parts of numbers are always numbers. |
| 12816 | Classical mereology doesn't handle temporal or modal notions very well [Simons] |
| Full Idea: The underlying logic of classical extensional mereology does not have the resources to deal with temporal and modal notions such as temporary part, temporal part, essential part, or essential permanent part. | |
| From: Peter Simons (Parts [1987], Intro) | |
| A reaction: Simons tries to rectify this in the later chapters of his book, with modifications rather than extensions. Since everyone struggles with temporal and modal issues of identity, we shouldn't judge too harshly. |
| 12821 | The part-relation is transitive and asymmetric (and thus irreflexive) [Simons] |
| Full Idea: Formally, the part-relation is transitive and asymmetric (and thus irreflexive). Hence nothing is a proper part of itself, things aren't proper parts of one another, and if one is part of two which is part of three then one is part of three. | |
| From: Peter Simons (Parts [1987], 1.1.1) |
| 18847 | Each wheel is part of a car, but the four wheels are not a further part [Simons] |
| Full Idea: The four wheels of a car are parts of it (each is part of it), but there is not a fifth part consisting of the four wheels. | |
| From: Peter Simons (Parts [1987], 4.6) | |
| A reaction: This raises questions about the transitivity of parthood. If there are parts of parts of wholes, the basic parts are OK, and the whole is OK, but how can there also be an intermediate part? Try counting the parts of this whole! |
| 12813 | Two standard formalisations of part-whole theory are the Calculus of Individuals, and Mereology [Simons] |
| Full Idea: The standardly accepted formal theory of part-whole is classical extensional mereology, which is known in two logical guises, the Calculus of Individuals of Leonard and Goodman, and the Mereology of Lesniewski. | |
| From: Peter Simons (Parts [1987], Intro) | |
| A reaction: Simons catalogues several other modern attempts at axiomatisation in his chapter 2. |
| 12846 | A 'group' is a collection with a condition which constitutes their being united [Simons] |
| Full Idea: We call a 'collection' of jewels a 'group' term. Several random musicians are unlikely to be an orchestra. If they come together regularly in a room to play, such conditions are constitutive of an orchestra. | |
| From: Peter Simons (Parts [1987], 4.4) | |
| A reaction: Clearly this invites lots of borderline cases. Eleven footballers don't immediately make a team, as followers of the game know well. |
| 12861 | 'The wolves' are the matter of 'the pack'; the latter is a group, with different identity conditions [Simons] |
| Full Idea: 'The wolves' is a plural term referring to just these animals, whereas 'the pack' of wolves refers to a group, and the group and plurality, while they may coincide in membership, have different identity conditions. The wolves are the matter of the pack. | |
| From: Peter Simons (Parts [1987], 6.4) | |
| A reaction: Even a cautious philosopher like Simons is ready to make bold ontological commitment to 'packs', on the basis of something called 'identity conditions'. I think it is just verbal. You can qualify 'the wolves' and 'the pack' to make them identical. |
| 12848 | The same members may form two groups [Simons] |
| Full Idea: Groups may coincide in membership without being identical - extensionality goes. | |
| From: Peter Simons (Parts [1987], 4.9) | |
| A reaction: Thus an eleven-person orchestra may also constitute a football team. What if a pile of stones is an impediment to you, and useful to me? Is it then two groups? Suppose they hum while playing football? (Don't you just love philosophy?) |
| 12876 | Philosophy is stuck on the Fregean view that an individual is anything with a proper name [Simons] |
| Full Idea: Modern philosophy is still under the spell of Frege's view that an individual is anything that has a proper name. (Note: But not only are empty names now recognised, but some are aware of the existence of plural reference). | |
| From: Peter Simons (Parts [1987], 8.1) | |
| A reaction: Presumably every electron in the universe is an individual, and every (finite) number which has never been named has a pretty clear identity. Presumably Pegasus, John Doe, and 'the person in the kitchen' have to be accommodated. |
| 12845 | Some natural languages don't distinguish between singular and plural [Simons] |
| Full Idea: The syntactic distinction between singular and plural is not a universal feature of natural languages. Chinese manages nicely without it, and Sanskrit makes a tripartite distinction between singular, dual, and plural (more than two). | |
| From: Peter Simons (Parts [1987], 4.3) | |
| A reaction: Simons is mounting an attack on the way in which modern philosophy and logic has been mesmerised by singular terms and individuated objects. Most people seem now to agree with Simons. There is stuff, as well as plurals. |
| 12838 | Four-dimensional ontology has no change, since that needs an object, and time to pass [Simons] |
| Full Idea: In the four-dimensional ontology there may be timeless variation, but there is no change. Change consists in an object having first one property and then another contrary one. But processes all have their properties timelessly. | |
| From: Peter Simons (Parts [1987], 3.4) | |
| A reaction: Possibly Simons is begging the question here. The phenomena which are traditionally labelled as 'change' are all nicely covered in the four-D account. Change is, we might say, subsumed in the shape of the space-time 'worm'. |
| 12842 | There are real relational changes, as well as bogus 'Cambridge changes' [Simons] |
| Full Idea: It is a mistake to call bogus Cambridge changes 'relational changes', since there are real relational changes, such as the changes in the relative positions and distances of several bodies. | |
| From: Peter Simons (Parts [1987], 4.1) | |
| A reaction: I'm not sure how you distinguish the two. If we swap seats, that is a real change. If everyone moves away from where I am sitting, is that real or Cambridge? If I notice, I might be upset, but suppose I don't notice? Nothing about me changes. |
| 12841 | I don't believe in processes [Simons] |
| Full Idea: I have been unable to see that there are processes. | |
| From: Peter Simons (Parts [1987], 4.1 n4) | |
| A reaction: My problem here is that I am inclined to think of the mind as a process of the brain. The fact that a reductive account can be given of a process doesn't mean that we can deny there existence. Is there no such thing as decay, or erosion? |
| 12836 | Fans of process ontology cheat, since river-stages refer to 'rivers' [Simons] |
| Full Idea: Proponents of process ontology (except perhaps Whitehead, who is obscure) indulge in double-talk with concrete examples. It is cheating to talk of 'cat-processes', or 'bathing in river-stages'. You can't change the subject and leave the predicate alone. | |
| From: Peter Simons (Parts [1987], 3.4) | |
| A reaction: It is one thing to admit processes into one's ontology, and another to have a 'process ontology', which presumably reduces objects to processes. I suppose the interest of continuant objects is precisely the aspect of them that is above any process. |
| 12880 | Moments are things like smiles or skids, which are founded on other things [Simons] |
| Full Idea: A 'moment' is something which is founded on something else. Examples are legion: smiles, headaches, gestures, skids, collisions, fights, thought, all founded on their participants, the continuants involved in them. | |
| From: Peter Simons (Parts [1987], 8.4) | |
| A reaction: The idea of a 'moment' and 'foundation' come from Husserl Log. Inv. 3. Simons says moments 'have a bright future in ontology'. It would be better if fewer of his examples involved human beings and their perceptions. |
| 12881 | A smiling is an event with causes, but the smile is a continuant without causes [Simons] |
| Full Idea: A smiling, being an event, has causes and effects, whereas the smile thereby produced is a continuant, and has itself neither causes nor effects. | |
| From: Peter Simons (Parts [1987], 8.5) | |
| A reaction: This is dogmatic, hopeful and a bit dubious. Simons is very scathing about processes in ontology. There seem to be two descriptions, with distinctive syntax, but it is hard to believe that in reality we have two types of thing present. |
| 12883 | Moving disturbances are are moments which continuously change their basis [Simons] |
| Full Idea: Moving disturbances are a special and interesting kind of continuant: moments which continuously change their fundaments. | |
| From: Peter Simons (Parts [1987], 8.5) | |
| A reaction: [a smile is a moment, and the face its fundament] I'm thinking he's got this wrong. Compare Idea 12882. Disturbances can't be continuants, because the passing of time is essential to them, but not to a continuant. |
| 12882 | A wave is maintained by a process, but it isn't a process [Simons] |
| Full Idea: A wave is maintained by a process transferring motion from particle to particle of the medium, but it is not identical with this process. | |
| From: Peter Simons (Parts [1987], 8.5) | |
| A reaction: I'm inclined to think of the mind as a process. There are some 'things' which only seem to exist if they have a duration. Bricks can be instantaneous, but minds and waves can't. A wave isn't a continuant. A hill isn't a wave. |
| 12840 | I do not think there is a general identity condition for events [Simons] |
| Full Idea: Like Anscombe (1979) I do not think there is such a creature as a general identity condition for events. | |
| From: Peter Simons (Parts [1987], 4.1 n1) | |
| A reaction: My working definition of an event is 'any part of a process which can be individuated'. This leaves you trying to define a process, and define individuate, and then to realise that individuation is not an objective matter. |
| 12839 | Relativity has an ontology of things and events, not on space-time diagrams [Simons] |
| Full Idea: A closer examination of the concepts and principles of relativity shows that they rest squarely on an ontology of things and events (not on convenient 'space-time diagrams'). Acceleration concerns non-zero mass, but only continuants can have a mass. | |
| From: Peter Simons (Parts [1987], 3.4) | |
| A reaction: The point here is that fans of four-dimensionalism like to claim that they are more in touch with modern physics, because 'time is just another dimension, like space, so objects are spread across it'. Simons sounds right about this. |
| 12879 | Independent objects can exist apart, and maybe even entirely alone [Simons] |
| Full Idea: An object a is ontologically independent of b if a can exist without b, if there is a possible world in which in which a exists and b does not. In the strongest sense, an object is independent if it could be all there is. | |
| From: Peter Simons (Parts [1987], 8.4) | |
| A reaction: Simons calls the strongest version a 'startling' one which maybe not even God could achieve. |
| 12847 | Mass nouns admit 'much' and 'a little', and resist 'many' and 'few'. [Simons] |
| Full Idea: Syntactic criteria for mass nouns include that they admit 'much' and 'a little', and resist 'many' and 'few'. | |
| From: Peter Simons (Parts [1987], 4.6) | |
| A reaction: That is, they don't seem to be countable. Sortal terms are those which pick out countables. |
| 12863 | Mass terms (unlike plurals) are used with indifference to whether they can exist in units [Simons] |
| Full Idea: Mass terms and plural terms differ principally in the indifference of mass terms to matters of division. A mass term can be used irrespective of how, indeed whether, the denotatum comes parcelled in units. | |
| From: Peter Simons (Parts [1987], 6.4) | |
| A reaction: It seems more to the point to say that mass terms (stuff) don't need units to exist, and you can disperse the units (the cups of water) without affecting the identity of the stuff. You can't pulverise a pile of stones and retain the stones. |
| 12862 | Gold is not its atoms, because the atoms must be all gold, but gold contains neutrons [Simons] |
| Full Idea: The mass of gold cannot be identified with the gold atoms, because whatever is part of the gold atoms is gold, whereas not every part of the gold is gold (for example, the neutrons in it are not gold). | |
| From: Peter Simons (Parts [1987], 6.4) | |
| A reaction: There is something too quick about arguments like this. It comes back to nominal v real essence. We apply 'gold' to the superficial features of the stuff, but deep down we may actually mean the atomic structure. See Idea 12812. |
| 12859 | A mixture can have different qualities from its ingredients. [Simons] |
| Full Idea: The qualities of a mixture need not be those of its ingredients in isolation. | |
| From: Peter Simons (Parts [1987], 6.2) | |
| A reaction: It depends on what you mean by a quality. Presumably we can give a reductive account of the qualities of the mixture, as long as no reaction has taken place. The taste of a salad is just the sum of its parts. |
| 12858 | Mixtures disappear if nearly all of the mixture is one ingredient [Simons] |
| Full Idea: If a cupful of dirty water is mixed evenly with a ton of earth, no dirty water remains, and the same goes if we mix it evenly with a lake of clean water. | |
| From: Peter Simons (Parts [1987], 6.2) | |
| A reaction: This means that a mixture is a vague entity, subject to the sorites paradox. If the dirt was cyanide, we would consider the water to be polluted by it down to a much lower level. |
| 12850 | To individuate something we must pick it out, but also know its limits of variation [Simons] |
| Full Idea: We have not finished deciding what Fido is when we can pick him out from his surroundings at any one time. ...Knowing what Fido is depends on knowing roughly within what limits his flux of parts is tolerable. | |
| From: Peter Simons (Parts [1987], 5.2) | |
| A reaction: I like this. We don't know the world until we know its modal characteristics (its powers or dispositions). Have you 'individuated' a hand grenade if you think it is a nice ornament? |
| 12860 | Sortal nouns for continuants tell you their continuance- and cessation-conditions [Simons] |
| Full Idea: A sortal noun for a kind of continuant tells us, among other things, under what conditions the object continues to exist and under what conditions it ceases to exist. | |
| From: Peter Simons (Parts [1987], 6.3) | |
| A reaction: This sounds blatantly false. If you know something is a 'snake', that doesn't tell you how hot it must get before the snakes die. Obviously if you know all about snakes (from studying individual snakes!), then you know a lot about the next snake. |
| 12886 | A whole requires some unique relation which binds together all of the parts [Simons] |
| Full Idea: A whole must at least approximate to this condition: every member of some division of the object stands in a certain relation to every other member, and no member bears this relation to anything other than members of the division. | |
| From: Peter Simons (Parts [1987], 9.2) | |
| A reaction: Simons proceeds to formalise this, and I suspect that he goes for this definition because (unlike looser ones) it can be formalised. See Simons's Idea 12865. We'll need to know whether these are internal or external relations. |
| 12835 | Does Tibbles remain the same cat when it loses its tail? [Simons] |
| Full Idea: The cat is 'Tibbles' with a tail; 'Tib' is Tibbles after the loss of the tail. 1) Tibbles isn't Tib at t; 2) Tibbles is Tib at t'; 3) Tibbles at t is Tibbles at t'; 4) Tib at t is Tib at t'; so 5) Tibbles at t is Tib at t (contradicting 1). What's wrong? | |
| From: Peter Simons (Parts [1987], 3.3) | |
| A reaction: [The example is in Wiggins 1979, from Geach, from William of Sherwood] Simons catalogues nine assumptions which are being made to produce the contradiction. 1) rests on Leibniz's law. Simons says two objects are occupying Tibbles. |
| 12857 | Tibbles isn't Tib-plus-tail, because Tibbles can survive its loss, but the sum can't [Simons] |
| Full Idea: There mere fact that Tibbles can survive the mutilation of losing a tail, whereas the sum of Tib and the tail cannot, is enough to distinguish them, even if no such mutilation ever occurs. | |
| From: Peter Simons (Parts [1987], 6.1) | |
| A reaction: See Idea 12835 for details of the Tibbles example. Either we go for essentialism here, or the whole notion of identity collapses. But the essential features of a person are not just those whose loss would kill them. |
| 12820 | Without extensional mereology two objects can occupy the same position [Simons] |
| Full Idea: If we reject extensionality in mereology, it has as a consequence that more than one object may have exactly the same parts at the same time, and hence occupy the same position. | |
| From: Peter Simons (Parts [1987], Intro) | |
| A reaction: Simons defends this claim. I'm unconvinced that we must choose between the two views. The same parts should ensure the same physical essence, which seems to guarantee the same identity. Not any old parts generate an essence. |
| 12866 | Composition is asymmetric and transitive [Simons] |
| Full Idea: Composition is asymmetric and transitive: if a is made up of b, and b of c, then a is made up of c; and if a is made of b, then b is not made up of a. We cannot say the snow is made up of the snowball. | |
| From: Peter Simons (Parts [1987], 6.5) | |
| A reaction: ...And snowballs composed of snow can then compose a snowman (transitivity). |
| 12867 | A hand constitutes a fist (when clenched), but a fist is not composed of an augmented hand [Simons] |
| Full Idea: Composition entails constitution, but does the converse hold? A hand constitutes a fist in virtue of being clenched, but it is not obvious that it composes a fist, and certainly a fist is not composed of a hand plus some additional part. | |
| From: Peter Simons (Parts [1987], 6.5) | |
| A reaction: There are subtleties of ordinary usage in 'compose' and 'constitute' which are worth teasing apart, but that isn't the last word on such relationships. 'Compose' seems to point towards matter, while 'constitute' seems to point towards form. |
| 12864 | We say 'b is part of a', 'b is a part of a', 'b are a part of a', or 'b are parts of a'. [Simons] |
| Full Idea: There are four cases of possible forms of expression when a is made up of b: we say 'b is part of a', or 'b is a part of a', or 'b are a part of a', or 'b are parts of a'. | |
| From: Peter Simons (Parts [1987], 6.4) | |
| A reaction: Personally I don't want to make much of these observations of normal English usage, but they are still interesting, and Simons offers a nice discussion of them. |
| 12814 | Classical mereology says there are 'sums', for whose existence there is no other evidence [Simons] |
| Full Idea: Either out of conviction or for reasons of algebraic neatness, classical extensional mereology asserts the existence of certain individuals, mereological sums, for whose existence in general we have no evidence outside the theory itself. | |
| From: Peter Simons (Parts [1987], Intro) | |
| A reaction: Observing that we have no evidence for sums 'outside the theory' is nice. It is a nice ontological test, with interesting implications for Quinean ontological commitment. |
| 12817 | 'Mereological extensionality' says objects with the same parts are identical [Simons] |
| Full Idea: Classical extensional mereology won't extend well to temporal and modal facts, because of 'mereological extensionality', which is the thesis that objects with the same parts are identical (by analogy with the extensionality of sets). | |
| From: Peter Simons (Parts [1987], Intro) | |
| A reaction: Simons challenges this view, claiming, for example, that the Ship of Theseus is two objects rather than one. I suppose 'my building bricks' might be 'your sculpture', but this is very ontologically extravagant. This is a mereological Leibniz's Law. |
| 12833 | If there are c atoms, this gives 2^c - 1 individuals, so there can't be just 2 or 12 individuals [Simons] |
| Full Idea: In classical mereology, if there are c atoms, where c is any cardinal number, there are 2^c - 1 individuals, so the cardinality of models is restricted. There are no models with cardinality 2, 12 or aleph-0, for example. | |
| From: Peter Simons (Parts [1987], 1.2) | |
| A reaction: The news that there is no possible world containing just 2 or just 12 individuals ought to worry fans of extensional mereology. A nice challenge for God - create a world containing just 12 individuals. |
| 12849 | Sums are more plausible for pluralities and masses than they are for individuals [Simons] |
| Full Idea: We are on stronger grounds in asserting the general existence of sums when considering pluralities and masses than when considering individuals. | |
| From: Peter Simons (Parts [1987], 5.2) | |
| A reaction: I was thinking that the modern emphasis on referring to plurals was precisely to resist the idea that we must 'sum' them into one thing. If so, we wouldn't want to then sum several plurals. If a mass isn't a sum, how can we sum some masses? |
| 12877 | Sums of things in different categories are found within philosophy. [Simons] |
| Full Idea: Cross-categorial sums are not unknown in philosophy. A body and the events which befall it are intimately connected, and the mysterious four-dimensional blocks might be mereological sums of the body and its life. | |
| From: Peter Simons (Parts [1987], 8.1) | |
| A reaction: Simons here ventures into the territory of abstracta, which he said he wouldn't touch. Presumably his first example has 'a biography' as its whole, which is not just a philosophical notion. Why will some categories sum, and others won't? |
| 12888 | The wholeness of a melody seems conventional, but of an explosion it seems natural [Simons] |
| Full Idea: The example of a melody shows that what counts as a temporal individual is partly a matter of human stipulation. But with a natural event like an explosion there is little or no room for decision about what is a part, and whether it is a single event. | |
| From: Peter Simons (Parts [1987], 9.6) | |
| A reaction: You could have a go at giving a natural account of the wholeness of a melody, in terms of the little aesthetic explosion that occurs in the brain of a listener. |
| 12871 | Objects have their essential properties because of the kind of objects they are [Simons] |
| Full Idea: An object has the essential properties it has in virtue of being the kind of object it is. | |
| From: Peter Simons (Parts [1987], 7.1) | |
| A reaction: He attributes this to Husserl and Wiggins. I just don't get it. What makes something the 'kind of object it is'? They've got it the wrong way round. Does God announce that this thing is a tiger, and is then pleasantly surprised to discover its stripes? |
| 12870 | We must distinguish the de dicto 'must' of propositions from the de re 'must' of essence [Simons] |
| Full Idea: We must distinguish the 'must' of necessity as applied to a proposition or state of affairs (de dicto) from the 'must' of essence, concerning the way in which an object has an attribute (de re). | |
| From: Peter Simons (Parts [1987], 7.1) | |
| A reaction: A helfpful distinction, but a possible confusion of necessity and essentiality (Simons knows this). Modern logicians seem to run them together, because they only care about identity. I don't, because I care about explanations. |
| 12873 | Original parts are the best candidates for being essential to artefacts [Simons] |
| Full Idea: Original parts are the best candidates for being essential to artefacts. It is hard to conceive how an object could have as essential a part which was attached at some time after the object had come into being. | |
| From: Peter Simons (Parts [1987], 7.4) | |
| A reaction: Without its big new memory upgrade my computer would be hopelessly out of date. Simons is awesome in some ways, but seems rather confused when it comes to discussing essence. I think Wiggins may have been a bad influence on him. |
| 12874 | An essential part of an essential part is an essential part of the whole [Simons] |
| Full Idea: An essential part of an essential part is an essential part of the whole. | |
| From: Peter Simons (Parts [1987], 7.4) | |
| A reaction: Sounds beyond dispute, but worth pondering. It seems to be only type-parts, not token-parts, which are essential. Simons is thinking of identity rather than function, but he rejects Chisholm's idea that all parts are essential. So which ones are? |
| 12837 | Four dimensional-objects are stranger than most people think [Simons] |
| Full Idea: The strangeness of four-dimensional objects is almost always underestimated in the literature. | |
| From: Peter Simons (Parts [1987], 3.4) | |
| A reaction: See Idea 12836, where he has criticised process ontologists for smuggling in stages and process as being OF conventional objects. |
| 12856 | Intermittent objects would be respectable if they occurred in nature, as well as in artefacts [Simons] |
| Full Idea: If we could show that intermittence could occur not only among artefacts and higher-order objects, but also among natural things, then we should have given it a secure place on the ontological map. | |
| From: Peter Simons (Parts [1987], 5.7) | |
| A reaction: Interesting ontological test. Having identified fairly clear intermittent artefacts (Idea 12851), if we then fail to find any examples in nature, must we revisit the artefacts and say they are not intermittents? He suggests freezing an organ in surgery. |
| 12885 | Objects like chess games, with gaps in them, are thereby less unified [Simons] |
| Full Idea: Temporal objects which are scattered in time - i.e. have temporal gaps in them, like interrupted discussions or chess games - are less unified than those without gaps. | |
| From: Peter Simons (Parts [1987], 9.2) | |
| A reaction: Is he really saying that a discussion or a chess game is less unified if there is even the slightest pause in it? Otherwise, how long must the pause be before it disturbs the unity? Do people play internet chess, as they used to play correspondence chess? |
| 12854 | An entrepreneur and a museum curator would each be happy with their ship at the end [Simons] |
| Full Idea: At the end of the Ship of Theseus story both an entrepreneur and a museum curator can be content, each having his ship all to himself, ..because each was all along claiming a different object from the other. | |
| From: Peter Simons (Parts [1987], 5.5) | |
| A reaction: Simons has the entrepreneur caring about function (for cruises), and the curator caring about matter (as a relic of Theseus). It is bold of Simons to say on that basis that it starts as two objects, one 'matter-constant', the other 'form-constant'. |
| 12855 | The 'best candidate' theories mistakenly assume there is one answer to 'Which is the real ship?' [Simons] |
| Full Idea: The 'best candidate' theories get into difficulty because it is assumed that there is a single uniquely correct answer to the question 'Which is the real ship?' | |
| From: Peter Simons (Parts [1987], 5.5) | |
| A reaction: My own example supports Simons. If Theseus discards the old planks as rubbish, then his smart new ship is the original. But if he steals his own ship (to evade insurance regulations) by substituting a plank at a time, the removed planks are the original. |
| 12872 | The zygote is an essential initial part, for a sexually reproduced organism [Simons] |
| Full Idea: It is essential to an organism arising from sexual reproduction that it has its zygote as initial improper part. | |
| From: Peter Simons (Parts [1987], 7.3) | |
| A reaction: It can't be necessary that an organism which appears to be sexually reproduced actually is so (if you don't believe that, read more science fiction). It may well just be analytic that sexual reproduction involves a zygote. Nothing to do with essence. |
| 12889 | The limits of change for an individual depend on the kind of individual [Simons] |
| Full Idea: What determines the limits of admissible change and secures the identity of a continuant is a matter of the kind of object in question. | |
| From: Peter Simons (Parts [1987], 9.6) | |
| A reaction: This gives some motivation for the sortal view of essence, which I find hard to take. However, if my statue were pulverised it would make good compost. |
| 7458 | The reliability of witnesses depends on whether they benefit from their observations [Laplace, by Hacking] |
| Full Idea: The credibility of a witness is in part a function of the story being reported. When the story claims to have infinite value, the temptation to lie for personal benefit is asymptotically infinite. | |
| From: report of Pierre Simon de Laplace (Philosophical Essay on Probability [1820], Ch.XI) by Ian Hacking - The Emergence of Probability Ch.8 | |
| A reaction: Laplace seems to especially have reports of miracles in mind. This observation certainly dashes any dreams one might have of producing a statistical measure of the reliability of testimony. |
| 3441 | If a supreme intellect knew all atoms and movements, it could know all of the past and the future [Laplace] |
| Full Idea: An intelligence knowing at an instant the whole universe could know the movement of the largest bodies and atoms in one formula, provided his intellect were powerful enough to subject all data to analysis. Past and future would be present to his eyes. | |
| From: Pierre Simon de Laplace (Philosophical Essay on Probability [1820]), quoted by Mark Thornton - Do we have free will? p.70 |
| 12843 | With activities if you are doing it you've done it, with performances you must finish to have done it [Simons] |
| Full Idea: Action theorists distinguish between activity verbs such as 'weep' and 'talk' (where continuous entails perfect - John is weeping so John has now wept), and performance verbs like 'wash', where John is washing doesn't yet mean John has washed. | |
| From: Peter Simons (Parts [1987], 4.2) | |
| A reaction: How to distinguish them, bar examples? In 'has wept' and 'has washed', I'm thinking that it is the 'has' which is ambiguous, rather than the more contentful word. One is 'has participated' and the other is 'has completed'. I've participated in washing! |
| 12875 | One false note doesn't make it a performance of a different work [Simons] |
| Full Idea: A performance of a certain work with a false note is still a performance of that work, albeit a slightly imperfect one, and not (as Goodman has argued) a performance of a different work. | |
| From: Peter Simons (Parts [1987], 7.6) | |
| A reaction: This is clearly right, but invites the question of how many wrong notes are permissable. One loud very wrong note could ruin a very long performance (but of that work, presumably). This is about classical music, but think about jazz. |
| 21167 | Gravity is unusual, in that it always attracts and never repels [New Sci.] |
| Full Idea: Gravity is an odd sort of force, not least because it only ever works one way. Electromagnetism attracts and repels, but with gravity there are only positive masses always attract. | |
| From: New Scientist writers (Why the Universe Exists [2017], 05) | |
| A reaction: This leads to speculation about anti-gravity, but there is no current evidence for it. |
| 21176 | In the Big Bang general relativity fails, because gravity is too powerful [New Sci.] |
| Full Idea: At the origin of the universe gravity becomes so powerful that general relativity breaks down, giving infinity for every answer. | |
| From: New Scientist writers (Why the Universe Exists [2017], 09) |
| 21147 | Quantum electrodynamics incorporates special relativity and quantum mechanics [New Sci.] |
| Full Idea: The theory of electromagnetism that incorporates both special relativity and quantum mechanics is quantum electrodynamics (QED). It was developed by Dirac and others, and perfected in the 1940s. The field is a collection of quanta. | |
| From: New Scientist writers (Why the Universe Exists [2017], 02) | |
| A reaction: This builds on Maxwell's earlier classical theory. QED is said to be the best theory in all of physics. |
| 21155 | Photons have zero rest mass, so virtual photons have infinite range [New Sci.] |
| Full Idea: Photons, the field quanta of the electromagnetic force, have zero rest mass, so virtual photons can exist indefinitely and travel any distance, meaning the electromagnetic force has an infinite range. | |
| From: New Scientist writers (Why the Universe Exists [2017], 02) |
| 21161 | In the standard model all the fundamental force fields merge at extremely high energies [New Sci.] |
| Full Idea: The standard model says that the fields of all fundamental forces should merge at extremely high energies, meaning there is also a unified, high-energy field out there. | |
| From: New Scientist writers (Why the Universe Exists [2017], 03) | |
| A reaction: Not quite sure what 'out there' means. This idea is linked to the quest for dark energy. Is this unified phenomenon only found near the Big Bang? |
| 21146 | Electrons move fast, so are subject to special relativity [New Sci.] |
| Full Idea: Electrons in atoms move at high speeds, so they are subject to the special theory of relativity. | |
| From: New Scientist writers (Why the Universe Exists [2017], 02) | |
| A reaction: Presumably this implies a frame of reference, and defining velocities relative to other electrons. Plus time-dilation? |
| 21148 | The strong force is repulsive at short distances, strong at medium, and fades at long [New Sci.] |
| Full Idea: Experiments show that the nuclear binding force does not follow the inverse square law, but is repulsive at the shortest distances, then attractive, then fades away rapidly as distance increases further. | |
| From: New Scientist writers (Why the Universe Exists [2017], 02) | |
| A reaction: So how does it know when to be strong? Magnetism doesn't vary according to distance, and light obeys the inverse square law, because everything is decided at the output. - See 21151 for an explanation. It interacts after departure. |
| 21152 | The strong force binds quarks tight, and the nucleus more weakly [New Sci.] |
| Full Idea: The strong force holds quarks together within protons and neutrons, and residual effects of the strong force bind protons (whch repel one another) and neutrons together in nuclei. | |
| From: New Scientist writers (Why the Universe Exists [2017], 02) | |
| A reaction: So the force is much stronger between quarks (which can't escape), and only 'residual' in the nucleus, which must be why smashing nuclei open is fairly easy, but smashin protons open needs higher energies. |
| 21151 | Gluons, the particles carrying the strong force, interact because of their colour charge [New Sci.] |
| Full Idea: In QCD the particles that carry the strong force are called gluons. ...Gluons carry their own colour charges, so they can interact with each other (unlike photons) via the strong nuclear force (which limits the range of the force). | |
| From: New Scientist writers (Why the Universe Exists [2017], 02) | |
| A reaction: So the force varies in strength with distance because the degree of separation among the spreading gluons varies? The force has one range, which is squashed when close, effective at medium, and loses touch with distance? |
| 21142 | Classifying hadrons revealed two symmetry patterns, produced by three basic elements [New Sci.] |
| Full Idea: Classifying hadrons according to charge, strangeness and spin revealed patterns of eight and ten particles (SU(3) symmetery). The mathematics then showed that these are built from a basic group of only three members. | |
| From: New Scientist writers (Why the Universe Exists [2017], 01) |
| 21150 | Three different colours of quark (as in the proton) can cancel out to give no colour [New Sci.] |
| Full Idea: Just as mixing three colours of light gives white, so the three colour charges of quarks can add up to give no colour. This is what happens in the proton, which always contains one blue-charge quark, one red and one green. | |
| From: New Scientist writers (Why the Universe Exists [2017], 02) |
| 21143 | Quarks in threes can build hadrons with spin ½ or with spin 3/2 [New Sci.] |
| Full Idea: Quarks in threes can build hadrons with spin ½ (proton, duu; neutron, ddu; lambda, dus), or with spin 3/2 (omega-minus, sss). | |
| From: New Scientist writers (Why the Universe Exists [2017], 01) |
| 21154 | Three particles enable the weak force: W+ and W- are charged, and Z° is not [New Sci.] |
| Full Idea: The quantum field theory of the weak force needs three carrier particles. The W+ and W- are electrically charged, and enable the weak force to change the charge of a particle. The Z° is uncharged, and mediates weak interactions with no charge change. | |
| From: New Scientist writers (Why the Universe Exists [2017], 02) |
| 21156 | The weak force particles are heavy, so the force has a short range [New Sci.] |
| Full Idea: The W and Z particles are heavy, and so cannot travel far from their parents. The weak force therefore has a very short range. | |
| From: New Scientist writers (Why the Universe Exists [2017], 02) |
| 21145 | The four fundamental forces (gravity, electromagnetism, weak and strong) are the effects of particles [New Sci.] |
| Full Idea: There are four fundamental forces: gravity, electromagnetism, and the weak and strong nuclear forces. Particle physics has so far failed to encompass the force of gravity. The forces that shape our world are themselves the effect of particles. | |
| From: New Scientist writers (Why the Universe Exists [2017], 02) | |
| A reaction: Philosophers must take note of the fact that forces are the effects of particles. Common sense pictures forces imposed on particles, like throwing a tennis ball, but the particles are actually the sources of force. The gravitino is speculative. |
| 21153 | The weak force explains beta decay, and the change of type by quarks and leptons [New Sci.] |
| Full Idea: The beta decay of the neutron (into a proton, an electron and an antineutrino) can be described in terms of the weak force, which is 10,000 times weaker than the strong force. It allows the quarks and leptons to change from one type to another. | |
| From: New Scientist writers (Why the Universe Exists [2017], 02) | |
| A reaction: This seems to make it the key source of radioactivity. Perhaps it should be called the Force of Change? |
| 21164 | Why do the charges of the very different proton and electron perfectly match up? [New Sci.] |
| Full Idea: Why do the proton and electron charges mirror each other so perfectly when they are such different particles? | |
| From: New Scientist writers (Why the Universe Exists [2017], 04) | |
| A reaction: We seem to have reached a common stage in science, where we have a wonderful descriptive model (the Standard Model), but we cannot explain why what is modelled is the way it is. |
| 21170 | The Standard Model cannot explain dark energy, survival of matter, gravity, or force strength [New Sci.] |
| Full Idea: The standard model cannot explain dark matter, or dark energy (which is causing expansion to accelerate). It cannot explain how matter survived annihilation with anti-matter in the Big Bang, or explain gravity. The strength of each force is unexplained. | |
| From: New Scientist writers (Why the Universe Exists [2017], 06) | |
| A reaction: [compressed] P.141 adds that the model has to be manipulated to keep the Higgs mass low enough. |
| 21158 | Fermions, with spin ½, are antisocial, and cannot share quantum states [New Sci.] |
| Full Idea: Particles with half-integer spin, such as electrons, protons or quarks (all spin ½) have an asymmetry in their wavefunction that makes them antisocial. These particles (Fermions) cannot share a quantum state. | |
| From: New Scientist writers (Why the Universe Exists [2017], 02) | |
| A reaction: This is said to explain the complexity of matter, with carbon an especially good example. |
| 21165 | Spin is akin to rotation, and is easily measured in a magnetic field [New Sci.] |
| Full Idea: Spin is a quantum-mechanical property of a particle akin to rotation about its own axis. Particles of different spins respond to magnetic fields in different ways, so it is a relatively easy thing to measure. | |
| From: New Scientist writers (Why the Universe Exists [2017], 04) | |
| A reaction: I wish I knew what 'akin to' meant. Maybe particles are not rigid bodies, so they cannot spin in the way a top can? It must be an electro-magnetic property. Idea 21166 says spin has two possible directions. |
| 21157 | Particles are spread out, with wave-like properties, and higher energy shortens the wavelength [New Sci.] |
| Full Idea: Particles obeying the laws of quantum mechanics have wave-like properties - moving as a quantum wave-function, spread out in space, with wavelengths that get shorter as their energy increases. | |
| From: New Scientist writers (Why the Universe Exists [2017], 02) | |
| A reaction: Thus X-rays are dangerous, but long wave radio is not. De Broglie's equation. |
| 21149 | Quarks have red, green or blue colour charge (akin to electric charge) [New Sci.] |
| Full Idea: Quarks have a property akin to electric charge, called their colour charge. It comes in three varieties, red, green and blue. | |
| From: New Scientist writers (Why the Universe Exists [2017], 02) |
| 21140 | Spin is a built-in ration of angular momentum [New Sci.] |
| Full Idea: Spin is a built-in ration of angular momentum. | |
| From: New Scientist writers (Why the Universe Exists [2017], 01) | |
| A reaction: As an outsider all I can do is collect descriptions of such properties from the experts. The experts appear to be happy with the numbers inserted in the equations. |
| 21163 | The mass of protons and neutrinos is mostly binding energy, not the quarks [New Sci.] |
| Full Idea: Most of a proton's or neutrino's mass is contained in the interaction energies of a 'sea' of quarks, antiquarks and gluons that bind them. ...You might feel solid, but in fact you're 99 per cent binding energy. | |
| From: New Scientist writers (Why the Universe Exists [2017], 04) | |
| A reaction: This is because energy is equivalent to mass (although gluons are said to have energy but no mass - puzzled by that). This is a fact which needs a bit of time to digest. Once you've grasped we are full of space, you still have understood it. |
| 21168 | Gravitional mass turns out to be the same as inertial mass [New Sci.] |
| Full Idea: There are two types of mass: gravitational mass quantifies how strongly an object feels gravity, while inertial mass quantifies an object's resistance to acceleration. There proven equality is at the heart of General Relativity. | |
| From: New Scientist writers (Why the Universe Exists [2017], 05) | |
| A reaction: It had never occurred to me that these two values might come apart. Doesn't their identical values demonstrate that they are in fact the same thing? Sounds like Hesperus/Phosphorus to me. The book calls it 'mysterious'. |
| 21138 | Neutrons are slightly heavier than protons, and decay into them by emitting an electron [New Sci.] |
| Full Idea: The proton (938.3 MeV) is lighter than the neutron (939.6 MeV) and does not decay, but the heavier neutron can change into a proton by emitting an electron. (If you gather a bucketful of neutrons, after ten minutes only half of them would be left). | |
| From: New Scientist writers (Why the Universe Exists [2017], 01) | |
| A reaction: Protons are more or less eternal, but some theories have them decaying after billions of years. Smashing protons together is a popular pastime for physicists. |
| 21144 | Top, bottom, charm and strange quarks quickly decay into up and down [New Sci.] |
| Full Idea: Quarks can change from one variety to another, and the top, bottom, charm and strange quarks all rapidly decay to the up and down quarks of everyday life. | |
| From: New Scientist writers (Why the Universe Exists [2017], 01) | |
| A reaction: Hence the universe is largely composed of up and down quarks and electrons. The other quarks seem to be more important in the early universe. |
| 21141 | Neutrinos were proposed as the missing energy in neutron beta decay [New Sci.] |
| Full Idea: When a neutron decays into a proton and an electron (one example of beta decay), the energy of the two particles adds up to less than the starting energy of the neutron. Pauli and Fermi concluded that a neutrino (an electron antineutrino) is emitted. | |
| From: New Scientist writers (Why the Universe Exists [2017], 01) | |
| A reaction: I'm wondering how much they could infer about the nature of the new particle (which was only confirmed 26 years later). |
| 21169 | Only neutrinos spin anticlockwise [New Sci.] |
| Full Idea: Neutrinos are the only particles that seem just to spin anticlockwise. | |
| From: New Scientist writers (Why the Universe Exists [2017], 06) | |
| A reaction: See 21166. Anti-neutrino spin is the opposite way. Which way up do you hold the neutrino when pronouncing that it is 'anticlockwise? |
| 21166 | Standard antineutrinos have opposite spin and opposite lepton number [New Sci.] |
| Full Idea: In the conventional standard model neutrinos have antiparticles - which spin in the opposite direction, and have the opposite lepton number. | |
| From: New Scientist writers (Why the Universe Exists [2017], 05) |
| 21171 | The symmetry of unified electromagnetic and weak forces was broken by the Higgs field [New Sci.] |
| Full Idea: In the very early hot universe the electromagnetic and weak nuclear forces were one. The early emergence of the Higgs field led to electroweak symmetry breaking. The W and Z bosons grew fat, and the photon raced away mass-free. | |
| From: New Scientist writers (Why the Universe Exists [2017], 07) |
| 21175 | String theory might be tested by colliding strings to make bigger 'stringballs' [New Sci.] |
| Full Idea: A future accelerator might create 'stringballs', when two strings slam into one another and, rather than combining to form a stretched string, make a tangled ball. Finding them would prove string theory. | |
| From: New Scientist writers (Why the Universe Exists [2017], 08) | |
| A reaction: This is the only possible test for string theory which I have seen suggested. How do you 'slam strings together'? |
| 21177 | String theory offers a quantum theory of gravity, by describing the graviton [New Sci.] |
| Full Idea: String theory works as a quantum theory of gravity because string vibrations can describe gravitons, the hypothetical carriers of the gravitational force. | |
| From: New Scientist writers (Why the Universe Exists [2017], 09) | |
| A reaction: Presumably the main aim of a quantum theory of gravity is to include gravitons within particle theory. This idea has to be a main attraction of string theory. Compare Idea 21166. |
| 21178 | String theory is now part of 11-dimensional M-Theory, involving p-branes [New Sci.] |
| Full Idea: String theory has now been incorporated into Ed Witten's M-Theory, which is a mathematical framework that lives in 11-dimensional space-time, involving higher-dimensional objects called p-branes, of which strings are a special case. | |
| From: New Scientist writers (Why the Universe Exists [2017], 09) |
| 21179 | Supersymmetric string theory can be expressed using loop quantum gravity [New Sci.] |
| Full Idea: String theory, together with its supersymmetric particles, has recently been rewritten in the space-time described by loop quantum gravity (which says that space-time ust be made from finite chunks). | |
| From: New Scientist writers (Why the Universe Exists [2017], 09) |
| 21162 | Only supersymmetry offers to incorporate gravity into the scheme [New Sci.] |
| Full Idea: Peter Higgs says he is a fan of supersymmetry, largely because it seems to be the only route by which gravity can be brought into the scheme. | |
| From: New Scientist writers (Why the Universe Exists [2017], 03) | |
| A reaction: Peter Higgs proposed the Higgs boson (now discovered). This seems a very good reason to favour supersymmetry. A grand unified theory that left out gravity doesn't seem to be unified quite grandly enough. |
| 21172 | The evidence for supersymmetry keeps failing to appear [New Sci.] |
| Full Idea: The old front-runner theory, supersymmetry, has fallen from grace as the Large Hadron Collider keeps failing to find it. | |
| From: New Scientist writers (Why the Universe Exists [2017], 07) |
| 21173 | Supersymmetry says particles and superpartners were unities, but then split [New Sci.] |
| Full Idea: The key to supersymmetry is that in the high-energy soup of the early universe, particles and their superpartners were indistinguishable. Each pair existed as single massless entities. With expansion and cooling this supersymmetry broke down. | |
| From: New Scientist writers (Why the Universe Exists [2017], 08) |
| 21159 | Supersymmetry has extra heavy bosons and heavy fermions [New Sci.] |
| Full Idea: Supersymmetry posits heavy boson partners for all fermions, and heavy fermions for all bosons. | |
| From: New Scientist writers (Why the Universe Exists [2017], 02) | |
| A reaction: The main Fermions are electron, proton and quark. Do extra bosons imply extra forces? Peter Higgs favours supersymmetry. |
| 21160 | The Higgs field means even low energy space is not empty [New Sci.] |
| Full Idea: The point about the Higgs field is that even the lowest-energy state of space is not empty. | |
| From: New Scientist writers (Why the Universe Exists [2017], 02) | |
| A reaction: So where is the Higgs field located? Even if there is no utterly empty space, the concept of location implies a concept of space more basic than the fields (about 16, I gather) which occupy it. You can't describe movement without a concept of location. |
| 21174 | Dark matter must have mass, to produce gravity, and no electric charge, to not reflect light [New Sci.] |
| Full Idea: Whatever dark matter is made of, it must have mass to feel and generate gravity; but no electric charge, so it does not interact with light. The leading candidate has been the weakly interacting massive particle (WIMP), much heavier than a proton. | |
| From: New Scientist writers (Why the Universe Exists [2017], 08) | |
| A reaction: Note that it must 'generate' gravity. The idea of a law of gravity which is externally imposed on matter is long dead. Heavy WIMPs have not yet been detected. |