44 ideas
| 21238 | Later phenomenologists tried hard to incorporate social relationships [Bakewell] |
| Full Idea: Ever since Husserl, phenomenologists and existentialists had been trying to stretch the definition of existence to incorporate our social lives and relationships. | |
| From: Sarah Bakewell (At the Existentialist Café [2016], 08) | |
| A reaction: I see a parallel move in Wittgenstein's Private Language Argument. Husserl's later work seems to have been along those lines. Putnam's Twin Earth too. |
| 21237 | Phenomenology begins from the immediate, rather than from axioms and theories [Bakewell] |
| Full Idea: Traditional philosophy often started with abstract axioms or theories, but the German phenomenologists went straight for life as they experienced it, moment to moment. | |
| From: Sarah Bakewell (At the Existentialist Café [2016], 01) | |
| A reaction: Bakewell gives this as the gist of what Aron said to Sartre in 1933, providing the bridge from phenomenology to existentialism. The obvious thought is that everybody outside philosophy starts from immediate experience, so why is this philosophy? |
| 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. |
| 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. |
| 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. |
| 20624 | Work degrades into heat, but not vice versa [Close] |
| Full Idea: William Thomson, Lord Kelvin, declared (in 1865) the second law of thermodynamics: mechanical work inevitably tends to degrade into heat, but not vice versa. | |
| From: Frank Close (Theories of Everything [2017], 3 'Perpetual') | |
| A reaction: The basis of entropy, which makes time an essential part of physics. Might this be the single most important fact about the physical world? |
| 20623 | First Law: energy can change form, but is conserved overall [Close] |
| Full Idea: The first law of thermodynamics : energy can be changed from one form to another, but is always conserved overall. | |
| From: Frank Close (Theories of Everything [2017], 3 'Perpetual') | |
| A reaction: So we have no idea what energy is, but we know it's conserved. (Daniel Bernoulli showed the greater the mean energy, the higher the temperature. James Joule showed the quantitative equivalence of heat and work p.26-7) |
| 20625 | Third Law: total order and minimum entropy only occurs at absolute zero [Close] |
| Full Idea: The third law of thermodynamics says that a hypothetical state of total order and minimum entropy can be attained only at the absolute zero temperature, minus 273 degrees Celsius. | |
| From: Frank Close (Theories of Everything [2017], 3 'Arrow') | |
| A reaction: If temperature is energetic movement of atoms (or whatever), then obviously zero movement is the coldest it can get. So is absolute zero an energy state, or an absence of energy? I have no idea what 'total order' means. |
| 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? |
| 20622 | All motions are relative and ambiguous, but acceleration is the same in all inertial frames [Close] |
| Full Idea: There is no absolute state of rest; only relative motions are unambiguous. Contrast this with acceleration, however, which has the same magnitude in all inertial frames. | |
| From: Frank Close (Theories of Everything [2017], 3 'Newton's') | |
| A reaction: It seems important to remember this, before we start trumpeting about the whole of physics being relative. ....But see Idea 20634! |
| 20628 | The electric and magnetic are tightly linked, and viewed according to your own motion [Close] |
| Full Idea: Electric and magnetic phenomena are profoundly intertwined; what you interpret as electric or magnetic thus depends on your own motion. | |
| From: Frank Close (Theories of Everything [2017], 3 'Light!') | |
| A reaction: This sounds like an earlier version of special relativity. |
| 20635 | The general relativity equations relate curvature in space-time to density of energy-momentum [Close] |
| Full Idea: The essence of general relativity relates 'curvature in space-time' on one side of the equation to the 'density of momentum and energy' on the other. ...In full, Einstein required ten equations of this type. | |
| From: Frank Close (Theories of Everything [2017], 5 'Gravity') | |
| A reaction: Momentum involves mass, and energy is equivalent to mass (e=mc^2). |
| 20627 | Electric fields have four basic laws (two by Gauss, one by Ampère, one by Faraday) [Close] |
| Full Idea: Four basic laws of electric and magnetic fields: Gauss's Law (about the flux produced by a field), Gauss's law of magnets (there can be no monopoles), Ampère's Law (fields on surfaces), and Farday's Law (accelerated magnets produce fields). | |
| From: Frank Close (Theories of Everything [2017], 3 'Light!') | |
| A reaction: [Highly compressed, for an overview. Close explains them] |
| 20630 | Light isn't just emitted in quanta called photons - light is photons [Close] |
| Full Idea: Planck had assumed that light is emitted in quanta called photons. Einstein went further - light is photons. | |
| From: Frank Close (Theories of Everything [2017], 3 'Light!') | |
| A reaction: The point is that light travels as entities which are photons, rather than the emissions being quantized packets of some other stuff. |
| 20637 | In general relativity the energy and momentum of photons subjects them to gravity [Close] |
| Full Idea: In Einstein's general theory, gravity acts also on energy and momentum, not simply on mass. For example, massless photons of light feel the gravitational attraction of the Sun and can be deflected. | |
| From: Frank Close (Theories of Everything [2017], 5 'Planck') | |
| A reaction: Ah, a puzzle solved. How come massless photons are bent by gravity? |
| 20629 | Electro-magnetic waves travel at light speed - so light is electromagnetism! [Close] |
| Full Idea: Faradays' measurements predicted the speed of electro-magnetic waves, which happened to be the speed of light, so Maxwell made an inspired leap: light is an electromagnetic wave! | |
| From: Frank Close (Theories of Everything [2017], 3 'Light!') | |
| A reaction: Put that way, it doesn't sound like an 'inspired' leap, because travelling at exactly the same speed seems a pretty good indication that they are the same sort of thing. (But I'm not denying that Maxwell was a special guy!) |
| 20632 | In QED, electro-magnetism exists in quantum states, emitting and absorbing electrons [Close] |
| Full Idea: Dirac created quantum electrodynamics (QED): the universal electro-magnetic field can exist in discreet states of energy (with photons appearing and disappearing by energy excitations. This combined classical ideas, quantum theory and special relativity. | |
| From: Frank Close (Theories of Everything [2017], 3 'Light!') | |
| A reaction: Close says this is the theory of everything in atomic structure, but not in nuclei (which needs QCD and QFD). So if there are lots of other 'fields' (e.g. gravitational, weak, strong, Higgs), how do they all fit together? Do they talk to one another? |
| 20642 | Photon exchange drives the electro-magnetic force [Close] |
| Full Idea: The exchange of photons drives the electro-magnetic force. | |
| From: Frank Close (Theories of Everything [2017], 6 'Superstrings') | |
| A reaction: So light, which we just think of as what is visible, is a mere side-effect of the engine room of nature - the core mechanism of the whole electro-magnetic field. |
| 20639 | Quantum fields contain continual rapid creation and disappearance [Close] |
| Full Idea: Quantum field theory implies that the vacuum of space is filled with particles and antiparticles which bubble in and out of existence on faster and faster timescales over shorter and shorter distances. | |
| From: Frank Close (Theories of Everything [2017], 6 'Intro') | |
| A reaction: Ponder this sentence until you head aches. Existence, but not as we know it, Jim. Close says calculations in QED about the electron confirm this. |
| 20631 | Dirac showed how electrons conform to special relativity [Close] |
| Full Idea: In 1928 Paul Dirac discovered the quantum equation that describes the electron and conforms to the requirements special relativity theory. | |
| From: Frank Close (Theories of Everything [2017], 3 'Light!') | |
| A reaction: This sounds like a major step in the unification of physics. Quantum theory and General relativity remain irreconcilable. |
| 20641 | Electrons get their mass by interaction with the Higgs field [Close] |
| Full Idea: The electron gets its mass by interaction with the ubiquitous Higgs field. | |
| From: Frank Close (Theories of Everything [2017], 6 'Hierarchy') | |
| A reaction: I thought I understood mass until I read this. Is it just wrong to say the mass of a table is the 'amount of stuff' in it? |
| 20626 | Modern theories of matter are grounded in heat, work and energy [Close] |
| Full Idea: The link between temperature, heat, work and energy is at the root of our historical ability to construct theories of matter, such as Newton's dynamics, while ignoring, and indeed being ignorant of - atomic dimensions. | |
| From: Frank Close (Theories of Everything [2017], 3 'Arrow') | |
| A reaction: That is, presumably, that even when you fill in the atoms, and the standard model of physics, these aspects of matter do the main explaiining (of the behaviour, rather than of the structure). |
| 20633 | The Higgs field is an electroweak plasma - but we don't know what stuff it consists of [Close] |
| Full Idea: In 2012 it was confirmed that we are immersed in an electroweak plasma - the Higgs field. We curently have no knowledge of what this stuff might consist of. | |
| From: Frank Close (Theories of Everything [2017], 4 'Higgs') | |
| A reaction: The second sentence has my full attention. So we don't understand a field properly until we understand the 'stuff' it is made of? So what are all the familiar fields made of? Tell me more! |
| 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? |
| 20640 | Space-time is indeterminate foam over short distances [Close] |
| Full Idea: At very short distances, space-time itself becomes some indeterminate foam. | |
| From: Frank Close (Theories of Everything [2017], 6 'Intro') | |
| A reaction: [see Close for a bit more detail of this weird idea] |
| 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. |
| 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. |
| 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. |
| 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. |