38 ideas
| 19504 | My modus ponens might be your modus tollens [Pritchard,D] |
| Full Idea: One philosopher's modus ponens is another philosopher's modus tollens. | |
| From: Duncan Pritchard (Epistemological Disjunctivism [2012], 3.§2) | |
| A reaction: [Anyone know the originator of this nice thought?] You say A is true, and A proves B, so B is true. I reply that if A proves something as daft as B, then so much the worse for A. Ain't it the truth? |
| 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. |
| 8628 | I hold that algebra and number are developments of logic [Jevons] |
| Full Idea: I hold that algebra is a highly developed logic, and number but logical discrimination. | |
| From: William S. Jevons (The Principles of Science [1879], p.156), quoted by Gottlob Frege - Grundlagen der Arithmetik (Foundations) §15 | |
| A reaction: Thus Frege shows that logicism was an idea that was in the air before he started writing. Riemann's geometry and Boole's logic presumably had some influence here. |
| 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. |
| 19503 | An improbable lottery win can occur in a nearby possible world [Pritchard,D] |
| Full Idea: Low probability events such as lottery wins can occur in nearby possible worlds. | |
| From: Duncan Pritchard (Epistemological Disjunctivism [2012], 2.n2) | |
| A reaction: This seems to ruin any chance of mapping probabilities and counterfactuals in the neat model of nested possible worlds (like an onion). [Lewis must have thought of this, surely? - postcards, please] |
| 19505 | Moore begs the question, or just offers another view, or uses 'know' wrongly [Pritchard,D, by PG] |
| Full Idea: The three main objections to Moore's common-sense refutation of scepticism is that it either begs the question, or it just offers a rival view instead of a refutation, or it uses 'know' in a conversationally inappropriate way. | |
| From: report of Duncan Pritchard (Epistemological Disjunctivism [2012], 3.§2) by PG - Db (ideas) | |
| A reaction: [I deserve applause for summarising two pages of Pritchard's wordy stuff so neatly] |
| 19499 | We can have evidence for seeing a zebra, but no evidence for what is entailed by that [Pritchard,D] |
| Full Idea: The closure principle forces us to regard Zula as knowing that what she is looking at is not a cleverly disguised mule, and yet she doesn't appear to have any supporting evidence for this knowledge. | |
| From: Duncan Pritchard (Epistemological Disjunctivism [2012], 2.§3) | |
| A reaction: [Zula observes a zebra in the zoo] Entailment is a different type of justification from perception. If we add fallibilism to the mix, then fallibility can increase as we pursue a string of entailments. But proper logic, of course, should not be fallible. |
| 19500 | Favouring: an entailment will give better support for the first belief than reason to deny the second [Pritchard,D] |
| Full Idea: The Favouring Principle says that if S knows two things, and that the first entails the second, then S has better evidence in support of her belief in the first than she has for denying the second. | |
| From: Duncan Pritchard (Epistemological Disjunctivism [2012], 2.§3) | |
| A reaction: [his version is full of Greek letters, but who wants that stuff?] Pritchard concludes that if you believe in the closure principle then you should deny the favouring principle. |
| 19502 | Maybe knowledge just needs relevant discriminations among contrasting cases [Pritchard,D] |
| Full Idea: According to the 'contrastivist' proposal knowledge is to be understood as essentially involving discrimination, such that knowing a proposition boils down to having the relevant discriminatory capacities. | |
| From: Duncan Pritchard (Epistemological Disjunctivism [2012], 2.§6) | |
| A reaction: Pritchard says this isn't enough, and we must also to be aware of supporting favouring evidence. I would focus on the concept of coherence, even for simple perceptual knowledge. If I see a hawk in England, that's fine. What if I 'see' a vulture? |
| 19498 | Epistemic internalism usually says justification must be accessible by reflection [Pritchard,D] |
| Full Idea: Typically, internal epistemic conditions are characterised in terms of a reflective access requirement. | |
| From: Duncan Pritchard (Epistemological Disjunctivism [2012], 1.§6) | |
| A reaction: If your justification is straightforwardly visual, it is unclear what the difference would be between seeing the thing and having reflective access to the seeing. |
| 19506 | Externalism is better than internalism in dealing with radical scepticism [Pritchard,D] |
| Full Idea: Standard epistemic internalism faces an uphill struggle when it comes to dealing with radical scepticism, which points in favour of epistemic externalist neo-Mooreanism. | |
| From: Duncan Pritchard (Epistemological Disjunctivism [2012], 3.§3) | |
| A reaction: I incline towards internalism. I deal with scepticism by being a fallibilist, and adding 'but you never know' to every knowledge claim, and then getting on with life. |
| 19496 | Disjunctivism says perceptual justification must be both factual and known by the agent [Pritchard,D] |
| Full Idea: Slogan for disjunctivism: perceptual knowledge is paradigmatically constituted by a true belief whose epistemic support is both factive (i.e. it entails the truth of the propositions believed) and reflectively accessible to the agent. | |
| From: Duncan Pritchard (Epistemological Disjunctivism [2012], Intro) | |
| A reaction: I'm not a fan of externalism, but it could be that the factive bit achieves the knowledge, and then being able to use and answer for that knowledge may just be a bonus, and not an essential ingredient. |
| 19497 | Metaphysical disjunctivism says normal perceptions and hallucinations are different experiences [Pritchard,D] |
| Full Idea: Metaphysical disjunctivists hold that veridical perceptual experiences are not essentially the same as the experiences involved in corresponding cases involving illusion and (especially) hallucination. | |
| From: Duncan Pritchard (Epistemological Disjunctivism [2012], 1.§4) | |
| A reaction: Metaphysical disjunctivism concerns what the experiences are; epistemological justification concerns the criteria of justification. I think. I wish Pritchard would spell things out more clearly. Indeed, I wish all philosophers would. |
| 19495 | Epistemic externalism struggles to capture the idea of epistemic responsibility [Pritchard,D] |
| Full Idea: A fundamental difficulty for epistemic externalist positions is that it is hard on this view to capture any adequate notion of epistemic responsibility. | |
| From: Duncan Pritchard (Epistemological Disjunctivism [2012], Intro) | |
| A reaction: He never explains the 'responsibility', but I presume that would be like an expert witness in court, vouching for their knowledge. |
| 19501 | We assess error against background knowledge, but that is just what radical scepticism challenges [Pritchard,D] |
| Full Idea: When faced with an error-possibility we can appeal to background knowledge, as long as the error-possibility does not call into question this background knowledge. The same is not true when we focus on the radical sceptical hypothesis. | |
| From: Duncan Pritchard (Epistemological Disjunctivism [2012], 2.§5) | |
| A reaction: [reworded] Doubting everything simultaneously just looks like a mad project. If you doubt linguistic meaning, you can't even express your doubts. |
| 19507 | Radical scepticism is merely raised, and is not a response to worrying evidence [Pritchard,D] |
| Full Idea: Crucially, radical sceptical error-possibilities are never epistemically motivated, but are instead merely raised. | |
| From: Duncan Pritchard (Epistemological Disjunctivism [2012], 3.§5) | |
| A reaction: In 'The Matrix' someone sees a glitch in the software (a cat crossing a passageway), and that would have to be taken seriously. Otherwise it is a nice strategy to ask why the sceptic is raising this bizzare possibility, without evidence. |
| 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. |