42 ideas
| 9065 | S5 collapses iterated modalities (◊□P→□P, and ◊◊P→◊P) [Keefe/Smith] |
| Full Idea: S5 collapses iterated modalities (so ◊□P → □P, and ◊◊P → ◊P). | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §5) | |
| A reaction: It is obvious why this might be controversial, and there seems to be a general preference for S4. There may be confusions of epistemic and ontic (and even semantic?) possibilities within a single string of modalities. |
| 22886 | The modern idea of 'limit' allows infinite quantities to have a finite sum [Bardon] |
| Full Idea: The concept of a 'limit' allows for an infinite number of finite quantities to add up to a finite sum. | |
| From: Adrian Bardon (Brief History of the Philosophy of Time [2013], 1 'Aristotle's') | |
| A reaction: This is only if the terms 'converge' on some end point. Limits are convenient fictions. |
| 13007 | Archimedes defined a straight line as the shortest distance between two points [Archimedes, by Leibniz] |
| Full Idea: Archimedes gave a sort of definition of 'straight line' when he said it is the shortest line between two points. | |
| From: report of Archimedes (fragments/reports [c.240 BCE]) by Gottfried Leibniz - New Essays on Human Understanding 4.13 | |
| A reaction: Commentators observe that this reduces the purity of the original Euclidean axioms, because it involves distance and measurement, which are absent from the purest geometry. |
| 22914 | An equally good question would be why there was nothing instead of something [Bardon] |
| Full Idea: If there were nothing, then wouldn't it be just as good a question to ask why there is nothing rather than something? There are many ways for there to be something, but only one way for there to be nothing. | |
| From: Adrian Bardon (Brief History of the Philosophy of Time [2013], 8 'Confronting') | |
| A reaction: [He credits Nozick with the question] I'm not sure whether there being nothing counts as a 'way' of being. If something exists it seems to need a cause, but no cause seems required for the absence of things. Nice, though. |
| 9064 | Objects such as a cloud or Mount Everest seem to have fuzzy boundaries in nature [Keefe/Smith] |
| Full Idea: A common intuition is that a vague object has indeterminate or fuzzy spatio-temporal boundaries, such as a cloud. Mount Everest can only have arbitrary boundaries placed around it, so in nature it must have fuzzy boundaries. | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §5) | |
| A reaction: We would have to respond by questioning whether Everest counts precisely as an 'object'. At the microscopic or subatomic level it seems that virtually everything has fuzzy boundaries. Maybe boundaries don't really exist. |
| 9044 | If someone is borderline tall, no further information is likely to resolve the question [Keefe/Smith] |
| Full Idea: If Tek is borderline tall, the unclarity does not seem to be epistemic, because no amount of further information about his exact height (or the heights of others) could help us decide whether he is tall. | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §1) | |
| A reaction: One should add also that information about social conventions or conventions about the usage of the word 'tall' will not help either. It seems fairly obvious that God would not know whether Tek is tall, so the epistemic view is certainly counterintuitive. |
| 9048 | The simplest approach, that vagueness is just ignorance, retains classical logic and semantics [Keefe/Smith] |
| Full Idea: The simplest approach to vagueness is to retain classical logic and semantics. Borderline cases are either true or false, but we don't know which, and, despite appearances, vague predicates have well-defined extensions. Vagueness is ignorance. | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §1) | |
| A reaction: It seems to me that you must have a rather unhealthy attachment to the logicians' view of the world to take this line. It is the passion of the stamp collector, to want everything in sets, with neatly labelled properties, and inference lines marked out. |
| 9055 | The epistemic view of vagueness must explain why we don't know the predicate boundary [Keefe/Smith] |
| Full Idea: A key question for the epistemic view of vagueness is: why are we ignorant of the facts about where the boundaries of vague predicates lie? | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §2) | |
| A reaction: Presumably there is a range of answers, from laziness, to inability to afford the instruments, to limitations on human perception. At the limit, with physical objects, how do we tell whether it is us or the object which is afflicted with vagueness? |
| 9049 | Supervaluationism keeps true-or-false where precision can be produced, but not otherwise [Keefe/Smith] |
| Full Idea: The supervaluationist view of vagueness is that 'tall' comes out true or false on all the ways in which we can make 'tall' precise. There is a gap for borderline cases, but 'tall or not-tall' is still true wherever you draw a boundary. | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §1) | |
| A reaction: [Kit Fine is the spokesperson for this; it preserves classical logic, but not semantics] This doesn't seem to solve the problem of vagueness, but it does (sort of) save the principle of excluded middle. |
| 9056 | Vague statements lack truth value if attempts to make them precise fail [Keefe/Smith] |
| Full Idea: The supervaluationist view of vagueness proposes that a sentence is true iff it is true on all precisifications, false iff false on all precisifications, and neither true nor false otherwise. | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §3) | |
| A reaction: This seems to be just a footnote to the Russell/Unger view, that logic works if the proposition is precise, but otherwise it is either just the mess of ordinary life, or the predicate doesn't apply at all. |
| 9058 | Some of the principles of classical logic still fail with supervaluationism [Keefe/Smith] |
| Full Idea: Supervaluationist logic (now with a 'definite' operator D) fails to preserve certain classical principles about consequence and rules of inference. For example, reduction ad absurdum, contraposition, the deduction theorem and argument by cases. | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §3) | |
| A reaction: The aim of supervaluationism was to try to preserve some classical logic, especially the law of excluded middle, in the face of problems of vagueness. More drastic views, like treating vagueness as irrelevant to logic, or the epistemic view, do better. |
| 9059 | The semantics of supervaluation (e.g. disjunction and quantification) is not classical [Keefe/Smith] |
| Full Idea: The semantics of supervaluational views is not classical. A disjunction can be true without either of its disjuncts being true, and an existential quantification can be true without any of its substitution instances being true. | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §3) | |
| A reaction: There is a vaguely plausible story here (either red or orange, but not definitely one nor tother; there exists an x, but which x it is is undecidable), but I think I will vote for this all being very very wrong. |
| 9060 | Supervaluation misunderstands vagueness, treating it as a failure to make things precise [Keefe/Smith] |
| Full Idea: Why should we think vague language is explained away by how things would be if it were made precise? Supervaluationism misrepresents vague expressions, as vague only because we have not bothered to make them precise. | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §3) | |
| A reaction: The theory still leaves a gap where vagueness is ineradicable, so the charge doesn't seem quite fair. Logicians always yearn for precision, but common speech enjoys wallowing in a sea of easy-going vagueness, which works fine. |
| 9050 | A third truth-value at borderlines might be 'indeterminate', or a value somewhere between 0 and 1 [Keefe/Smith] |
| Full Idea: One approach to predications in borderline cases is to say that they have a third truth value - 'neutral', 'indeterminate' or 'indefinite', leading to a three-valued logic. Or a degree theory, such as fuzzy logic, with infinite values between 0 and 1. | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §1) | |
| A reaction: This looks more like a strategy for computer programmers than for metaphysicians, as it doesn't seem to solve the difficulty of things to which no one can quite assign any value at all. Sometimes you can't be sure if an entity is vague. |
| 9061 | People can't be placed in a precise order according to how 'nice' they are [Keefe/Smith] |
| Full Idea: There is no complete ordering of people by niceness, and two people could be both fairly nice, nice to intermediate degrees, while there is no fact of the matter about who is the nicer. | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §4) | |
| A reaction: This is a difficulty if you are trying to decide vague predicates by awarding them degrees of truth. Attempts to place a precise value on 'nice' seem to miss the point, even more than utilitarian attempts to score happiness. |
| 9062 | If truth-values for vagueness range from 0 to 1, there must be someone who is 'completely tall' [Keefe/Smith] |
| Full Idea: Many-valued theories still seem to have a sharp boundary between sentences taking truth-value 1 and those taking value less than 1. So there is a last man in our sorites series who counts as 'completely tall'. | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §4) | |
| A reaction: Lovely. Completely nice, totally red, perfectly childlike, an utter mountain, one hundred per cent amused. The enterprise seems to have the same implausibility found in Bayesian approaches to assessing evidence. |
| 9063 | How do we decide if my coat is red to degree 0.322 or 0.321? [Keefe/Smith] |
| Full Idea: What could determine which is the correct function, settling that my coat is red to degree 0.322 rather than 0.321? | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §4) | |
| A reaction: It is not just the uncertainty of placing the coat on the scale. The two ends of the scale have all the indeterminacy of being red rather than orange (or, indeed, pink). You are struggling to find a spot on the ruler, when the ruler is placed vaguely. |
| 9045 | Vague predicates involve uncertain properties, uncertain objects, and paradoxes of gradual change [Keefe/Smith] |
| Full Idea: Three interrelated features of vague predicates such as 'tall', 'red', 'heap', 'child' are that they have borderline cases (application is uncertain), they lack well-defined extensions (objects are uncertain), and they're susceptible to sorites paradoxes. | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §1) | |
| A reaction: The issue will partly depend on what you think an object is: choose from bundles of properties, total denial, essential substance, or featureless substance with properties. The fungal infection of vagueness could creep in at any point, even the words. |
| 9047 | Many vague predicates are multi-dimensional; 'big' involves height and volume; heaps include arrangement [Keefe/Smith] |
| Full Idea: Many vague predicates are multi-dimensional. 'Big' of people depends on both height and volume; 'nice' does not even have clear dimensions; whether something is a 'heap' depends both the number of grains and their arrangement. | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §1) | |
| A reaction: Anyone who was hoping for a nice tidy theory for this problem should abandon hope at this point. Huge numbers of philosophical problems can be simplified by asking 'what exactly do you mean here?' (e.g. tall or bulky?). |
| 9053 | If there is a precise borderline area, that is not a case of vagueness [Keefe/Smith] |
| Full Idea: If a predicate G has a sharply-bounded set of cases falling in between the positive and negative, this shows that merely having borderline cases is not sufficient for vagueness. | |
| From: R Keefe / P Smith (Intro: Theories of Vagueness [1997], §1) | |
| A reaction: Thus you might have 'pass', 'fail' and 'take the test again'. But there seem to be two cases in the border area: will decide later, and decision seems impossible. And the sharp boundaries may be quite arbitrary. |
| 22902 | Why does an effect require a prior event if the prior event isn't a cause? [Bardon] |
| Full Idea: To say that a reaction requires the earlier presence of an action just raises anew the question of why it is 'required' if it isn't bring about the reaction. | |
| From: Adrian Bardon (Brief History of the Philosophy of Time [2013], 4 'Pervasive') | |
| A reaction: This is another example of my demand that empiricists don't just describe and report conjunctions and patterns, but make some effort to explain them. |
| 22905 | Becoming disordered is much easier for a system than becoming ordered [Bardon] |
| Full Idea: Systems move to a higher state of entropy …because there are very many more ways for a system to be disordered than for it to be ordered. …We can also say that they tend to move from a non-equilibrium state to an equilibrium state. | |
| From: Adrian Bardon (Brief History of the Philosophy of Time [2013], 5 'Thermodynamic') | |
| A reaction: Is it actually about order, or is it just that energy radiates, and thus disperses? |
| 22913 | The universe expands, so space-time is enlarging [Bardon] |
| Full Idea: More and more space-time is literally being created from nothing all the time as the universe expands. | |
| From: Adrian Bardon (Brief History of the Philosophy of Time [2013], 8 'Realism') | |
| A reaction: [He cites Paul Davies for this] Is the universe acquiring more space, or is the given space being stretched? Acquiring more time makes no sense, so what is more space-time? |
| 22889 | We should treat time as adverbial, so we don't experience time, we experience things temporally [Bardon, by Bardon] |
| Full Idea: Kant says that instead of focusing on the nouns 'time' and 'space', it would be more on target to focus on the adverbial applications of the concepts - that we don't experience things in time and space so much as experience them temporally and spatially. | |
| From: report of Adrian Bardon (Brief History of the Philosophy of Time [2013]) by Adrian Bardon - Brief History of the Philosophy of Time 2 'Kantian' | |
| A reaction: Put like that, Kant's approach has some plausibility, given that we don't actually experience space and time as entities. To jump from that to idealism seems daft. Does every adverb imply idealism about what it specifies? |
| 22900 | How can we question the passage of time, if the question takes time to ask? [Bardon] |
| Full Idea: Even questioning the passage of time may be self-defeating: can any question be meaningfully asked or understood without presuming the passage of time from the inception of the question to its conclusion? | |
| From: Adrian Bardon (Brief History of the Philosophy of Time [2013], 4 'Pervasive') | |
| A reaction: [He cites P.J. Zwart for this] We can at least, in B-series style, specify the starting and finishing times of the question, without talk of its passage. Nice point, though. |
| 22898 | What is time's passage relative to, and how fast does it pass? [Bardon] |
| Full Idea: If time is passing, then relative to what? How could time pass with respect to itself? Further, if time passes, at what rate does it pass? | |
| From: Adrian Bardon (Brief History of the Philosophy of Time [2013], 4 'Pervasive') | |
| A reaction: I remember some writer grasping the nettle, and saying that time passes at one second per second. Compare travelling at one metre per metre. |
| 22897 | The A-series says a past event is becoming more past, but how can it do that? [Bardon] |
| Full Idea: In the dynamic theory of time the Battle of Waterloo is become more past. If we insist on the A-series properties, this seems inevitable. But how can a past event be changing now? | |
| From: Adrian Bardon (Brief History of the Philosophy of Time [2013], 4 'Reasons') | |
| A reaction: [He cites Ulrich Meyer for this] We don't worry about an object changing its position when it is swept down a river. The location of the Battle of Waterloo relative to 'now' is not a property of the battle. That is a 'Cambridge' property. |
| 22901 | The B-series needs a revised view of causes, laws and explanations [Bardon] |
| Full Idea: If we accept the static (B-series) view, we have to reevaluate how we think about causation, natural laws, and scientific explanation. | |
| From: Adrian Bardon (Brief History of the Philosophy of Time [2013], 4 'Pervasive') | |
| A reaction: Any scientific account which refers to events seems to imply a dynamic view of time. Lots of scientists and philosophers endorse the static view of time, but then fail to pursue its implications. |
| 22896 | The B-series is realist about time, but idealist about its passage [Bardon] |
| Full Idea: The B-series theorist is a realist about time but an idealist about the passage of time. This is the Static Theory of time. | |
| From: Adrian Bardon (Brief History of the Philosophy of Time [2013], 4 'Reasons') | |
| A reaction: Note the both A and B are realists about time, and thus deny both the relationist and the idealist view. |
| 22903 | The B-series adds directionality when it accepts 'earlier' and 'later' [Bardon] |
| Full Idea: The static (B-series) theory, by embracing the relational temporal properties 'earlier' and 'later', adds a directional ordering to the block of events. | |
| From: Adrian Bardon (Brief History of the Philosophy of Time [2013], 5 'Time's') | |
| A reaction: I'm not clear whether this addition to the B-series picture is optional or obligatory. It is important that it seems to be a bolt-on feature, not immediately implied by the timeless series. What would Einstein say? |
| 22910 | To define time's arrow by causation, we need a timeless definition of causation [Bardon] |
| Full Idea: The problem for the causal analysis of temporal asymmetry is to come up with a definition of causation that does not itself rely on the concept of temporal asymmetry. | |
| From: Adrian Bardon (Brief History of the Philosophy of Time [2013], 5 'Causal') | |
| A reaction: This is the point at which my soul cries out 'time is a primitive concept!' Leibniz want to use dependency to define time's arrow, but how do you specify dependency if you don't know which one came first? |
| 22909 | We judge memories to be of the past because the events cause the memories [Bardon] |
| Full Idea: On the causal view of time's arrow, memories pertain to the 'past' just because they are caused by the events of which they are memories. | |
| From: Adrian Bardon (Brief History of the Philosophy of Time [2013], 5 'Causal') | |
| A reaction: How am I able to distinguish imagining the future from remembering the past? How do I tell which mental events have external causes, and which are generated by me? |
| 22904 | The psychological arrow of time is the direction from our memories to our anticipations [Bardon] |
| Full Idea: The psychological arrow of time refers to the familiar fact that that we remember (and never anticipate) the past, and anticipate (but never remember) the future. | |
| From: Adrian Bardon (Brief History of the Philosophy of Time [2013], 5 'Psychological') | |
| A reaction: Bardon rejects this on the grounds that the psychology is obviously the result of the actual order of events. Otherwise time's arrow would just result from the luck of how we individually experience things. |
| 22906 | The direction of entropy is probabilistic, not necessary, so cannot be identical to time's arrow [Bardon] |
| Full Idea: The coincidence of thermodynamic direction and the direction of time is striking, but they can't be one and the same because the thermodynamic law is merely probabilistic. Orderliness could increase, but it is highly improbable | |
| From: Adrian Bardon (Brief History of the Philosophy of Time [2013], 5 'Thermodynamic') | |
| A reaction: This seems to be persuasive grounds for rejecting thermodynamics as the explanation of time's arrow. |
| 22907 | It is arbitrary to reverse time in a more orderly universe, but not in a sub-system of it [Bardon] |
| Full Idea: It would seem arbitrary to say that the direction of time is reversed if the whole universe becomes more orderly, but it isn't reversed for any particular sub-system that becomes more orderly. | |
| From: Adrian Bardon (Brief History of the Philosophy of Time [2013], 5 'Thermodynamic') | |
| A reaction: The thought is that if time's arrow depends on entropy, then the arrow must reverse if entropy were to reverse (however unlikely). |
| 22883 | It seems hard to understand change without understanding time first [Bardon] |
| Full Idea: It is very tough to see how we could understand what change is without understanding what time is. | |
| From: Adrian Bardon (Brief History of the Philosophy of Time [2013], Intro) | |
| A reaction: This thought is aimed at those who are hoping to define time in terms of change. My working assumption is that time must be a primitive concept in any metaphysics. |
| 22890 | We experience static states (while walking round a house) and observe change (ship leaving dock) [Bardon] |
| Full Idea: We make a fundamental distinction between perceptions of static states and dynamic processes, …such as walking around a house, and watching a ship leave dock. | |
| From: Adrian Bardon (Brief History of the Philosophy of Time [2013], 2 'Kantian') | |
| A reaction: This seems to be a fundamental aspect of our mind, rather than of the raw experience (slightly supporting Kant). In both cases we experience a changing sequence, but we have two different interpretations of them. |
| 22884 | The motion of a thing should be a fact in the present moment [Bardon] |
| Full Idea: Whether or not something is in motion should be a fact about that thing now, not a fact about the thing in its past or in its future. | |
| From: Adrian Bardon (Brief History of the Philosophy of Time [2013], 1 'Arrow') | |
| A reaction: This is one of the present moment, in which nothing can occur if its magnitude is infinitely small. I have no solution to this problem. |
| 22892 | Experiences of motion may be overlapping, thus stretching out the experience [Bardon] |
| Full Idea: Experience itself may be constituted by overlapping, very brief, but temporally extended, acts of awareness, each of which encompassesa temporally extended streeeeetch of perceived events. | |
| From: Adrian Bardon (Brief History of the Philosophy of Time [2013], 2 'Realism') | |
| A reaction: [cites Barry Dainton 2000] I think this sounds better than Russell's suggestion, though along the same lines. I take all brain events to be a sort of memory, briefly retaining their experience. Very fast events blur because of overload. |
| 22911 | At least eternal time gives time travellers a possible destination [Bardon] |
| Full Idea: If all past, present and future events timelessly coexist, then at least there is a potential destination for the time traveller. …The Presentist treats past and future events as nonexistent, so there is no place for the time traveller to go. | |
| From: Adrian Bardon (Brief History of the Philosophy of Time [2013], 6 'Fictional') | |
| A reaction: Not a good reason to believe in the eternal block of time, of course. The growing block has a past which can be visited, but no future. |
| 22912 | Time travel is not a paradox if we include it in the eternal continuum of events [Bardon] |
| Full Idea: As long as we understand any time travel events to be timelessly included in the history of the world, and thus as part of the fixed continuum of events, time travel need not give rise to paradox. | |
| From: Adrian Bardon (Brief History of the Philosophy of Time [2013], 6 'Time travel') | |
| A reaction: This would presumably block going back and killing your own grandparent. |
| 22882 | We use calendars for the order of events, and clocks for their passing [Bardon] |
| Full Idea: Roughly speaking, we use calendars to track the order of events in time, and clocks to track changes and the passing of events. | |
| From: Adrian Bardon (Brief History of the Philosophy of Time [2013], Intro) | |
| A reaction: So calendars cover the B-Series and clocks the A-Series, showing that this distinction is deeply embedded, and wasn't invented by McTaggart. |