Ideas from 'Parts' by Peter Simons [1987], by Theme Structure

[found in 'Parts: a Study in Ontology' by Simons,Peter [OUP 1987,0-19-924146-5]].

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1. Philosophy / F. Analytic Philosophy / 1. Nature of Analysis
Analytic philosophers may prefer formal systems because natural language is such mess
                        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.
4. Formal Logic / G. Formal Mereology / 1. Mereology
Classical mereology doesn't apply well to the objects around us
                        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.
Complement: the rest of the Universe apart from some individual, written x-bar
                        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.
Criticisms of mereology: parts? transitivity? sums? identity? four-dimensional?
                        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.
A 'part' has different meanings for individuals, classes, and masses
                        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.
4. Formal Logic / G. Formal Mereology / 2. Terminology of Mereology
Proper or improper part: x < y, 'x is (a) part of y'
                        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.
Overlap: two parts overlap iff they have a part in common, expressed as 'x o y'
                        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.
Disjoint: two individuals are disjoint iff they do not overlap, written 'x | y'
                        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)
Product: the product of two individuals is the sum of all of their overlaps, written 'x · y'
                        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'.
Sum: the sum of individuals is what is overlapped if either of them are, written 'x + y'
                        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.
Difference: the difference of individuals is the remainder of an overlap, written 'x - y'
                        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)
General sum: the sum of objects satisfying some predicate, written σx(Fx)
                        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.
General product: the nucleus of all objects satisfying a predicate, written πx(Fx)
                        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.
Universe: the mereological sum of all objects whatever, written 'U'
                        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.
Atom: an individual with no proper parts, written 'At x'
                        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.
Dissective: stuff is dissective if parts of the stuff are always the stuff
                        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.
4. Formal Logic / G. Formal Mereology / 3. Axioms of Mereology
Two standard formalisations of part-whole theory are the Calculus of Individuals, and Mereology
                        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.
Classical mereology doesn't handle temporal or modal notions very well
                        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.
The part-relation is transitive and asymmetric (and thus irreflexive)
                        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)
Each wheel is part of a car, but the four wheels are not a further part
                        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!
4. Formal Logic / G. Formal Mereology / 4. Groups
A 'group' is a collection with a condition which constitutes their being united
                        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.
The same members may form two groups
                        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?)
'The wolves' are the matter of 'the pack'; the latter is a group, with different identity conditions
                        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.
5. Theory of Logic / F. Referring in Logic / 1. Naming / a. Names
Philosophy is stuck on the Fregean view that an individual is anything with a proper name
                        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.
5. Theory of Logic / G. Quantification / 6. Plural Quantification
Some natural languages don't distinguish between singular and plural
                        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.
7. Existence / B. Change in Existence / 1. Nature of Change
Four-dimensional ontology has no change, since that needs an object, and time to pass
                        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'.
There are real relational changes, as well as bogus 'Cambridge changes'
                        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.
7. Existence / B. Change in Existence / 2. Processes
I don't believe in processes
                        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?
Fans of process ontology cheat, since river-stages refer to 'rivers'
                        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.
7. Existence / B. Change in Existence / 3. Moments
A wave is maintained by a process, but it isn't a process
                        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.
Moments are things like smiles or skids, which are founded on other things
                        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.
Moving disturbances are are moments which continuously change their basis
                        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.
A smiling is an event with causes, but the smile is a continuant without causes
                        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.
7. Existence / B. Change in Existence / 4. Events / a. Nature of events
I do not think there is a general identity condition for events
                        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.
7. Existence / B. Change in Existence / 4. Events / b. Events as primitive
Relativity has an ontology of things and events, not on space-time diagrams
                        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.
7. Existence / C. Structure of Existence / 4. Ontological Dependence
Independent objects can exist apart, and maybe even entirely alone
                        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.
7. Existence / C. Structure of Existence / 8. Stuff / a. Pure stuff
Mass nouns admit 'much' and 'a little', and resist 'many' and 'few'.
                        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.
Gold is not its atoms, because the atoms must be all gold, but gold contains neutrons
                        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.
Mass terms (unlike plurals) are used with indifference to whether they can exist in units
                        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.
7. Existence / C. Structure of Existence / 8. Stuff / b. Mixtures
Mixtures disappear if nearly all of the mixture is one ingredient
                        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.
A mixture can have different qualities from its ingredients.
                        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.
9. Objects / A. Existence of Objects / 5. Individuation / a. Individuation
To individuate something we must pick it out, but also know its limits of variation
                        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?
9. Objects / A. Existence of Objects / 5. Individuation / e. Individuation by kind
Sortal nouns for continuants tell you their continuance- and cessation-conditions
                        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.
9. Objects / B. Unity of Objects / 1. Unifying an Object / a. Intrinsic unification
A whole requires some unique relation which binds together all of the parts
                        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.
9. Objects / B. Unity of Objects / 3. Unity Problems / b. Cat and its tail
Does Tibbles remain the same cat when it loses its tail?
                        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.
Tibbles isn't Tib-plus-tail, because Tibbles can survive its loss, but the sum can't
                        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.
9. Objects / B. Unity of Objects / 3. Unity Problems / d. Coincident objects
Without extensional mereology two objects can occupy the same position
                        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.
9. Objects / C. Structure of Objects / 5. Composition of an Object
Composition is asymmetric and transitive
                        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).
9. Objects / C. Structure of Objects / 6. Constitution of an Object
A hand constitutes a fist (when clenched), but a fist is not composed of an augmented hand
                        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.
9. Objects / C. Structure of Objects / 8. Parts of Objects / a. Parts of objects
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'.
                        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.
9. Objects / C. Structure of Objects / 8. Parts of Objects / b. Sums of parts
Classical mereology says there are 'sums', for whose existence there is no other evidence
                        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.
'Mereological extensionality' says objects with the same parts are identical
                        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.
If there are c atoms, this gives 2^c - 1 individuals, so there can't be just 2 or 12 individuals
                        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.
Sums are more plausible for pluralities and masses than they are for individuals
                        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?
Sums of things in different categories are found within philosophy.
                        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?
9. Objects / C. Structure of Objects / 8. Parts of Objects / c. Wholes from parts
The wholeness of a melody seems conventional, but of an explosion it seems natural
                        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.
9. Objects / D. Essence of Objects / 5. Essence as Kind
Objects have their essential properties because of the kind of objects they are
                        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?
9. Objects / D. Essence of Objects / 7. Essence and Necessity / b. Essence not necessities
We must distinguish the de dicto 'must' of propositions from the de re 'must' of essence
                        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.
9. Objects / D. Essence of Objects / 11. Essence of Artefacts
Original parts are the best candidates for being essential to artefacts
                        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.
9. Objects / D. Essence of Objects / 12. Essential Parts
An essential part of an essential part is an essential part of the whole
                        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?
9. Objects / E. Objects over Time / 4. Four-Dimensionalism
Four dimensional-objects are stranger than most people think
                        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.
9. Objects / E. Objects over Time / 7. Intermittent Objects
Intermittent objects would be respectable if they occurred in nature, as well as in artefacts
                        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.
Objects like chess games, with gaps in them, are thereby less unified
                        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?
9. Objects / E. Objects over Time / 9. Ship of Theseus
An entrepreneur and a museum curator would each be happy with their ship at the end
                        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'.
The 'best candidate' theories mistakenly assume there is one answer to 'Which is the real ship?'
                        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.
9. Objects / E. Objects over Time / 12. Origin as Essential
The zygote is an essential initial part, for a sexually reproduced organism
                        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.
10. Modality / E. Possible worlds / 3. Transworld Objects / a. Transworld identity
The limits of change for an individual depend on the kind of individual
                        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.
20. Action / A. Definition of Action / 2. Duration of an Action
With activities if you are doing it you've done it, with performances you must finish to have done it
                        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!
21. Aesthetics / B. Nature of Art / 8. The Arts / a. Music
One false note doesn't make it a performance of a different work
                        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.