28 ideas
| 18901 | Truthmakers are facts 'of' a domain, not something 'in' the domain [Sommers] |
| Full Idea: A fact is an existential characteristic 'of' the domain; it is not something 'in' the domain. To search for truth-making facts in the world is indeed futile. | |
| From: Fred Sommers (Intellectual Autobiography [2005], 'Existence') | |
| A reaction: Attacking Austin on truth. Helpful. It is hard to see how a physical object has a mysterious power to 'make' a truth. No energy-transfer seems involved in the making. Animals think true thoughts; I suspect that concerns their mental maps of the world. |
| 18904 | 'Predicable' terms come in charged pairs, with one the negation of the other [Sommers, by Engelbretsen] |
| Full Idea: Sommers took the 'predicable' terms of any language to come in logically charged pairs. Examples might be red/nonred, massive/massless, tied/untied, in the house/not in the house. The idea that terms can be negated was essential for such pairing. | |
| From: report of Fred Sommers (Intellectual Autobiography [2005]) by George Engelbretsen - Trees, Terms and Truth 2 | |
| A reaction: If, as Rumfitt says, we learn affirmation and negation as a single linguistic operation, this would fit well with it, though Rumfitt doubtless (as a fan of classical logic) prefers to negation sentences. |
| 18895 | Logic which maps ordinary reasoning must be transparent, and free of variables [Sommers] |
| Full Idea: What would a 'laws of thought' logic that cast light on natural language deductive thinking be like? Such a logic must be variable-free, conforming to normal syntax, and its modes of reasoning must be transparent, to make them virtually instantaneous. | |
| From: Fred Sommers (Intellectual Autobiography [2005], 'How We') | |
| A reaction: This is the main motivation for Fred Sommers's creation of modern term logic. Even if you are up to your neck in modern symbolic logic (which I'm not), you have to find this idea appealing. You can't leave it to the psychologists. |
| 18897 | Predicate logic has to spell out that its identity relation '=' is an equivalent relation [Sommers] |
| Full Idea: Because predicate logic contrues identities dyadically, its account of inferences involving identity propositions needs laws or axioms of identity, explicitly asserting that the dyadic realtion in 'x=y' possesses symmetry, reflexivity and transitivity. | |
| From: Fred Sommers (Intellectual Autobiography [2005], 'Syllogistic') |
| 18893 | Translating into quantificational idiom offers no clues as to how ordinary thinkers reason [Sommers] |
| Full Idea: Modern predicate logic's methods of justification, which involve translation into an artificial quantificational idiom, offer no clues to how the average person, knowing no logic and adhering to the vernacular, is so logically adept. | |
| From: Fred Sommers (Intellectual Autobiography [2005], Intro) | |
| A reaction: Of course, people are very logically adept when the argument is simple (because, I guess, they can test it against the world), but not at all good when the reasoning becomes more complex. We do, though, reason in ordinary natural language. |
| 18903 | Sommers promotes the old idea that negation basically refers to terms [Sommers, by Engelbretsen] |
| Full Idea: If there is one idea that is the keystone of the edifice that constitutes Sommers's united philosophy it is that terms are the linguistic entities subject to negation in the most basic sense. It is a very old idea, tending to be rejected in modern times. | |
| From: report of Fred Sommers (Intellectual Autobiography [2005]) by George Engelbretsen - Trees, Terms and Truth 2 | |
| A reaction: Negation in modern logic is an operator applied to sentences, typically writing '¬Fa', which denies that F is predicated of a, with Fa being an atomic sentence. Do we say 'not(Stan is happy)', or 'not-Stan is happy', or 'Stan is not-happy'? Third one? |
| 18894 | Predicates form a hierarchy, from the most general, down to names at the bottom [Sommers] |
| Full Idea: We organise our concepts of predicability on a hierarchical tree. At the top are terms like 'interesting', 'exists', 'talked about', which are predicable of anything. At the bottom are names, and in between are predicables of some things and not others. | |
| From: Fred Sommers (Intellectual Autobiography [2005], 'Category') | |
| A reaction: The heirarchy seem be arranged simply by the scope of the predicate. 'Tallest' is predicable of anything in principle, but only of a few things in practice. Is 'John Doe' a name? What is 'cosmic' predicable of? Challenging! |
| 18900 | Unfortunately for realists, modern logic cannot say that some fact exists [Sommers] |
| Full Idea: Unfortunately for the fate of realist philosophy, modern logic's treatment of 'exists' is resolutely inhospitable to facts as referents of phrases of the form 'the existence or non-existence of φ'. | |
| From: Fred Sommers (Intellectual Autobiography [2005], 'Realism') | |
| A reaction: Predicate logic has to talk about objects, and then attribute predicates to them. It tends to treat a fact as 'Fa' - this object has this predicate, but that's not really how we understand facts. |
| 13127 | Categories can't overlap; they are either disjoint, or inclusive [Sommers, by Westerhoff] |
| Full Idea: Fred Sommers, in his treatment of types, says that two ontological categories cannot overlap; they are either disjoint, or one properly includes the other. This is sometimes referred to as Sommers' Law. | |
| From: report of Fred Sommers (Types and Ontology [1963], p.355) by Jan Westerhoff - Ontological Categories §24 | |
| A reaction: The 'types', of course, go back to Bertrand Russell's theory of types, which is important in discussions of ontological categories. Carnap pursued it, trying to derive ontological categories from grammatical categories. 85% agree with Sommers. |
| 15127 | A categorical basis could hardly explain a disposition if it had no powers of its own [Hawthorne] |
| Full Idea: The categorical basis would be a poor explanans for the disposition as explanandum, if the categorical basis did not drag any causal powers along with it. | |
| From: John Hawthorne (Causal Structuralism [2001], 2.4) | |
| A reaction: The idea that the world is explained just by some basic stuff having qualities and relations always strikes me as wrong, because the view of nature is too passive. |
| 15123 | Is the causal profile of a property its essence? [Hawthorne] |
| Full Idea: We might say that the causal profile of a property is its essence. | |
| From: John Hawthorne (Causal Structuralism [2001], Intro) | |
| A reaction: I associate this view with Shoemaker, and find it sympathetic. We always want to know more. What gives rise to these causal powers? Where does explanation end? He notes that you might say some of the powers are non-essential. |
| 15122 | Could two different properties have the same causal profile? [Hawthorne] |
| Full Idea: If there is more to the nature of a property than the causal powers that it confers, then two different internal natures of properties might necessitate the same causal profile. | |
| From: John Hawthorne (Causal Structuralism [2001], Intro) | |
| A reaction: If the causal profiles were identical, it is hard to see how we could even propose, let alone test, their intrinsic difference. ...Unless, perhaps, we knew that the properties arose from different substrata. |
| 15124 | If properties are more than their powers, we could have two properties with the same power [Hawthorne] |
| Full Idea: If a property is something over and above its causal profile, we seem to have conceptual space for an electron to have negative charge 1 and negative charge 2, that have exactly the same causal powers. | |
| From: John Hawthorne (Causal Structuralism [2001], 1.3) |
| 14590 | If we accept scattered objects such as archipelagos, why not think of cars that way? [Hawthorne] |
| Full Idea: In being willing to countenance archipelagos, one embraces scattered objects. Why not then embrace the 'archipelago' of my car and the Eiffel Tower? | |
| From: John Hawthorne (Three-Dimensionalism v Four-Dimensionalism [2008], 2.1) | |
| A reaction: This is a beautifully simple and striking point. Language is full of embracing terms like 'the furniture', but that doesn't mean we assume the furniture is unified. The archipelago is less of an 'object' if you live on one of the islands. |
| 15128 | We can treat the structure/form of the world differently from the nodes/matter of the world [Hawthorne] |
| Full Idea: It does not seem altogether arbitrary to treat the structure of the world (the 'form' of the world) in a different way to the nodes in the structure (the 'matter' of the world). | |
| From: John Hawthorne (Causal Structuralism [2001], 2.5) | |
| A reaction: An interesting contemporary spin put on Aristotle's original view. Hawthorne is presenting the Aristotle account as a sort of 'structuralism' about nature. |
| 15121 | An individual essence is a necessary and sufficient profile for a thing [Hawthorne] |
| Full Idea: An individual essence is a profile that is necessary and sufficient for some particular thing. | |
| From: John Hawthorne (Causal Structuralism [2001], Intro) | |
| A reaction: By 'for' he presumably means for the thing to have an existence and a distinct identity. If it retained its identity, but didn't function any more, would that be loss of essence? |
| 14591 | Four-dimensionalists say instantaneous objects are more fundamental than long-lived ones [Hawthorne] |
| Full Idea: Self-proclaimed four-dimensionalists typically adopt a picture that reckons instantaneous objects (and facts about them) to be more fundamental than long-lived ones. | |
| From: John Hawthorne (Three-Dimensionalism v Four-Dimensionalism [2008], 2.2) | |
| A reaction: A nice elucidation. As in Idea 14588, this seems motivated by a desire for some sort of foundationalism or atomism. Why shouldn't a metaphysic treat the middle-sized or temporally extended as foundational, and derive the rest that way? |
| 8970 | Our notion of identical sets involves identical members, which needs absolute identity [Hawthorne] |
| Full Idea: Our conceptual grip on the notion of a set is founded on the axiom of extensionality: a set x is the same as a set y iff x and y have the same members. But this axiom deploys the notion of absolute identity ('same members'). | |
| From: John Hawthorne (Identity [2003], 3.1) | |
| A reaction: Identity seems to be a primitive, useful and crucial concept, so don't ask what it is. I suspect that numbers can't get off the ground without it (especially, in view of the above, if you define numbers in terms of sets). |
| 14589 | A modal can reverse meaning if the context is seen differently, so maybe context is all? [Hawthorne] |
| Full Idea: One person says 'He can't dig a hole; he hasn't got a spade', and another says 'He can dig a hole; just give him a spade', and both uses of the modal 'can' will be true. So some philosophers say that all modal predications are thus context-dependent. | |
| From: John Hawthorne (Three-Dimensionalism v Four-Dimensionalism [2008], 1.2) | |
| A reaction: Quine is the guru for this view of modality. Hawthorne's example seems to me to rely too much on the linguistic feature of contrasting 'can' and 'can't'. The underlying assertion in the propositions says something real about the possibilities. |
| 19553 | Commitment to 'I have a hand' only makes sense in a context where it has been doubted [Hawthorne] |
| Full Idea: If I utter 'I know I have a hand' then I can only be reckoned a cooperative conversant by my interlocutors on the assumption that there was a real question as to whether I have a hand. | |
| From: John Hawthorne (The Case for Closure [2005], 2) | |
| A reaction: This seems to point to the contextualist approach to global scepticism, which concerns whether we are setting the bar high or low for 'knowledge'. |
| 19551 | How can we know the heavyweight implications of normal knowledge? Must we distort 'knowledge'? [Hawthorne] |
| Full Idea: Those who deny skepticism but accept closure will have to explain how we know the various 'heavyweight' skeptical hypotheses to be false. Do we then twist the concept of knowledge to fit the twin desiderata of closue and anti-skepticism? | |
| From: John Hawthorne (The Case for Closure [2005], Intro) | |
| A reaction: [He is giving Dretske's view; Dretske says we do twist knowledge] Thus if I remember yesterday, that has the heavyweight implication that the past is real. Hawthorne nicely summarises why closure produces a philosophical problem. |
| 19552 | We wouldn't know the logical implications of our knowledge if small risks added up to big risks [Hawthorne] |
| Full Idea: Maybe one cannot know the logical consequences of the proposition that one knows, on account of the fact that small risks add up to big risks. | |
| From: John Hawthorne (The Case for Closure [2005], 1) | |
| A reaction: The idea of closure is that the new knowledge has the certainty of logic, and each step is accepted. An array of receding propositions can lose reliability, but that shouldn't apply to logic implications. Assuming monotonic logic, of course. |
| 19554 | Denying closure is denying we know P when we know P and Q, which is absurd in simple cases [Hawthorne] |
| Full Idea: How could we know that P and Q but not be in a position to know that P (as deniers of closure must say)? If my glass is full of wine, we know 'g is full of wine, and not full of non-wine'. How can we deny that we know it is not full of non-wine? | |
| From: John Hawthorne (The Case for Closure [2005], 2) | |
| A reaction: Hawthorne merely raises this doubt. Dretske is concerned with heavyweight implications, but how do you accept lightweight implications like this one, and then suddenly reject them when they become too heavy? [see p.49] |
| 18898 | In standard logic, names are the only way to refer [Sommers] |
| Full Idea: In modern predicate logic, definite reference by proper names is the primary and sole form of reference. | |
| From: Fred Sommers (Intellectual Autobiography [2005], 'Reference') | |
| A reaction: Hence we have to translate definite descriptions into (logical) names, or else paraphrase them out of existence. The domain only contains 'objects', so only names can uniquely pick them out. |
| 6005 | Animals are dangerous and nourishing, and can't form contracts of justice [Hermarchus, by Sedley] |
| Full Idea: Hermarchus said that animal killing is justified by considerations of human safety and nourishment and by animals' inability to form contractual relations of justice with us. | |
| From: report of Hermarchus (fragments/reports [c.270 BCE]) by David A. Sedley - Hermarchus | |
| A reaction: Could the last argument be used to justify torturing animals? Or could we eat a human who was too brain-damaged to form contracts? |
| 15126 | Maybe scientific causation is just generalisation about the patterns [Hawthorne] |
| Full Idea: Perhaps science doesn't need a robust conception of causation, and can get by with thinking of causal laws in a Humean way, as the simplest generalization over the mosaic. | |
| From: John Hawthorne (Causal Structuralism [2001], 1.5) | |
| A reaction: The Humean view he is referring to is held by David Lewis. That seems a council of defeat. We observe from a distance, but make no attempt to explain. |
| 15125 | We only know the mathematical laws, but not much else [Hawthorne] |
| Full Idea: We know the laws of the physical world, in so far as they are mathematical, pretty well, but we know nothing else about it. | |
| From: John Hawthorne (Causal Structuralism [2001], Ch.25) | |
| A reaction: Lovely remark [spotted by Hawthorne]. This sums up exactly what I take to be the most pressing issue in philosophy of science - that we develop a view of science that has space for the next step in explanation. |
| 14588 | Modern metaphysicians tend to think space-time points are more fundamental than space-time regions [Hawthorne] |
| Full Idea: Nowadays it is common for metaphysicians to hold both that space-time regions are less fundamental than the space-time points that compose them, and that facts about the regions are less fundamental than facts about the points and their arrangements. | |
| From: John Hawthorne (Three-Dimensionalism v Four-Dimensionalism [2008], 1) | |
| A reaction: I'm not quite sure what a physicist would make of this. It seems to be motivated by some a priori preference for atomism, and for system-building from minimal foundations. |