Let’s drop the talk of people, that’s too complicated. Really, I’m just asking about how ‘reality fluid’ talk gets applied to everyday things as opposed to ‘happenings’. The claim on the table is that everyday things (including people) are happenings, and I’m worried about that.
Suppose ‘being a combustion engine’ meant actually firing a piston and rotating the drive shaft 360 degrees. If that what it meant to be a combustion engine, then if I interrupted the action of the piston after it had only rotated the drive shaft 180 degrees, the thing before me wouldn’t be a combustion engine. At best it would be sort of half way there. The reason being that on this account of combustion engines, it takes time to be a combustion engine (specifically, the time it takes for the drive shaft to rotate 360 degrees).
If we did talk about combustion engines this way, for example, it wouldn’t be possible to point to a combustion engine in a photograph. We could point to something that might be a sort of temporal part of a combustion engine, but a photograph (which shows us only a moment of time) couldn’t capture a combustion engine any more than it could capture a piece of music, or the rotation of a ball, or a free throw or anything that consists in being a kind of motion.
But, at least so far as I know, a combustion engine, unlike a motion, is not divisible into temporal parts. If all happenings take time and are divisible into temporal parts, and if combustion engines are not so divisible, then combustion engines are not happenings. If they’re not happenings, how does ‘reality fluid’ talk apply to them?
EDIT:
yet others are quantum-random (for example, ion channel opening and closing is due to quantum-mechanical tunneling effects).
Really? That’s fascinating, I have to look that up.
a combustion engine, unlike a motion, is not divisible into temporal parts
A combustion engine is deterministic. The behavior of a combustion engine is defined by the underlying physics. If properly designed, tuned and started as prescribed, it will cause the drive shaft to rotate a number of turns. A complete specification of the engine is enough to predict what it will do. If you design something that gets stuck after half a turn, it’s not what most people would consider a proper combustion engine, despite outward appearances. If you want to use the term “reality fluid”, then its flow is determined by the initial conditions. You can call this flow “motion” if you like.
I think you think I’m saying something much more complicated than what I’m trying to say. Nothing I’m saying has anything to do with prediction, design, determinism, (not that I know of, anyway) and I’m certainly not saying that ‘reality fluid’ moves. By ‘motion’ I mean what happens when you throw a baseball.
The distinction I’m trying to draw is this: on the one hand, some things take time and have temporal parts (like a piece of music, a walk in the park, the life-cycle of a star, or the electrochemical processes in a neuron). Call these processes. These are opposed, on the other hand, to things which so far as I can see, don’t have temporal parts, like a trombone, a dog, an internal combustion engine, or a star. Call these fubs (I don’t have a good name).
If reality fluid is a way of talking about decoherence, and decoherence talk always involves distinctions of time, then can we use reality fluid talk to talk about how real fubs are? We could if all fubs were reducible to processes. That would be a surprising result. Are all fubs reducible to processes? If so, is this an eliminative reduction (fundamentally, there are no fubs)? If not...well, if not I have some other, even weirder questions.
You seem to have a philosophical approach to this, while I prefer instrumental reductionism. If a collection of “fubs” plus the rules of their behavior predict what these fubs do at any point in time, why do you need to worry about some “temporal parts”? If you take an MP3 file and a music player and press “start”, you will have music playing. If this time stuff sounds mysterious, consider Eliezer’s timeless picture, where these fubs are slices of the flow. You can generalize it somewhat to quantum things, but there will be gaps (denied by handwaving MWIers, explicit in shut-up-and-calculate), hence the probabilistic nature of it.
You seem to have a philosophical approach to this, while I prefer instrumental reductionism.
We share the impression that the right answer will be a reductive, empirically grounded one. We might differ on the instrumentalism part: I really do want to know what the furniture of the universe is. I have no intended use for such knowledge, and its predictive power is not so important. So far as I understand instrumentalism, you might just reply that I’m barking up the wrong tree. But in case I’m not...
But let me ask this question again directly, because I think I need an answer to understand where you’re coming from: are fubs (everyday objects like tables and chairs and people, or if you like elementary particles or whatever) reducible to processes at some level of physical explanation? Or is the whole idea of a fub incoherent? Is the question somehow incoherent? Or would you guess that when we arrive at the right physical theory, it will include reference to both processes (like decoherence, motion, heating, etc.) and fubs?
are fubs (everyday objects like tables and chairs and people, or if you like elementary particles or whatever) reducible to processes at some level of physical explanation?
Hmm, I’m not sure how to avoid repeating myself. I’ve already said, and so has Luke_A_Somers, that “fubs” are 3d spatial slices of 4d spacetime regions. If this statement does not make sense to you, we can try to dissect it further. is there a particular part of it that is problematic?
I’ve already said, and so has Luke_A_Somers, that “fubs” are 3d spatial slices of 4d spacetime regions.
Ah! I didn’t catch that. Thanks. Suppose a man-made satellite (Fubly 1) is released into (non-geosynchronous) orbit around the earth directly over Phoenix, Arizona. Each time it orbits the earth, it passes over Phoenix, and we can count its orbits this way. One orbit of Fubly 1 is extended in time in the sense that it takes one month (say) to get around the whole planet. In any time less than one month, the orbit is incomplete. So the orbit of Fubly 1 is temporally divisibile in the sense that if I divide it in half, I get two things neither of which is an orbit of Fubly 1, but both of which are parts of an orbit of Fubly 1.
Now, Fubly 1 itself seems different. Suppose Fubly 1 only completes one orbit and then is destroyed. Supposing it’s assembled and then immediately released, the spaciotemporal region that is Fubly 1 and the spaciotemporal region that is the orbit of Fubly 1 have the same extension in time. If I divide the spaciotemporal region of the orbit in half, time-wise, I get two halves of an orbit. If I divide the spacio-temporal region of Fubly 1 itself, I don’t get two halves of a satellite. Fubly 1 can’t be divided time-wise in the way its orbit and its lifespan can. Does that make any sense? My question, in case it does, is this ’Is the distinction I’ve just made likely to be meaningful in the correct physics, or is this a mere artifact of intuition and natural language?
Fubly 1 can’t be divided time-wise in the way its orbit and its lifespan can.
It’s already the result of such a division. As for orbits and lifespans, they are not physical objects but rather logical abstractions, just like language is (as opposed to the air released from the mouth of the speaker and the pressure waves hitting the ear of the listener).
If you mean that Fubly 1 is a given 3d slice, can Fubly 1 persist through time? I mean that if we take two temporally different 3d slices (one at noon, the other at 1:00PM), would they be the same Fubly 1? I suppose if we were to call them ‘the same’ it would be in virtue of a sameness of their 3d properties, abstracted from their temporal positions.
I don’t know what sameness is, sorry. It’s not a definition I have encountered in physics, and SEP is silent on the issue, as well. I sort of understand it intuitively, but I am not sure how you formalize it. Maybe you can think about it in terms of the non-conservation of the coarse grained area around the evolved distribution function, similar to the way Eliezer discussed the Liouville theorem in his Quantum Sequence. Maybe similar areas correspond to more sameness, or something. But this is a wild speculation, I haven’t tried to work through this.
Let’s drop the talk of people, that’s too complicated. Really, I’m just asking about how ‘reality fluid’ talk gets applied to everyday things as opposed to ‘happenings’. The claim on the table is that everyday things (including people) are happenings, and I’m worried about that.
Suppose ‘being a combustion engine’ meant actually firing a piston and rotating the drive shaft 360 degrees. If that what it meant to be a combustion engine, then if I interrupted the action of the piston after it had only rotated the drive shaft 180 degrees, the thing before me wouldn’t be a combustion engine. At best it would be sort of half way there. The reason being that on this account of combustion engines, it takes time to be a combustion engine (specifically, the time it takes for the drive shaft to rotate 360 degrees).
If we did talk about combustion engines this way, for example, it wouldn’t be possible to point to a combustion engine in a photograph. We could point to something that might be a sort of temporal part of a combustion engine, but a photograph (which shows us only a moment of time) couldn’t capture a combustion engine any more than it could capture a piece of music, or the rotation of a ball, or a free throw or anything that consists in being a kind of motion.
But, at least so far as I know, a combustion engine, unlike a motion, is not divisible into temporal parts. If all happenings take time and are divisible into temporal parts, and if combustion engines are not so divisible, then combustion engines are not happenings. If they’re not happenings, how does ‘reality fluid’ talk apply to them?
EDIT:
Really? That’s fascinating, I have to look that up.
A combustion engine is deterministic. The behavior of a combustion engine is defined by the underlying physics. If properly designed, tuned and started as prescribed, it will cause the drive shaft to rotate a number of turns. A complete specification of the engine is enough to predict what it will do. If you design something that gets stuck after half a turn, it’s not what most people would consider a proper combustion engine, despite outward appearances. If you want to use the term “reality fluid”, then its flow is determined by the initial conditions. You can call this flow “motion” if you like.
I think you think I’m saying something much more complicated than what I’m trying to say. Nothing I’m saying has anything to do with prediction, design, determinism, (not that I know of, anyway) and I’m certainly not saying that ‘reality fluid’ moves. By ‘motion’ I mean what happens when you throw a baseball.
The distinction I’m trying to draw is this: on the one hand, some things take time and have temporal parts (like a piece of music, a walk in the park, the life-cycle of a star, or the electrochemical processes in a neuron). Call these processes. These are opposed, on the other hand, to things which so far as I can see, don’t have temporal parts, like a trombone, a dog, an internal combustion engine, or a star. Call these fubs (I don’t have a good name).
If reality fluid is a way of talking about decoherence, and decoherence talk always involves distinctions of time, then can we use reality fluid talk to talk about how real fubs are? We could if all fubs were reducible to processes. That would be a surprising result. Are all fubs reducible to processes? If so, is this an eliminative reduction (fundamentally, there are no fubs)? If not...well, if not I have some other, even weirder questions.
You seem to have a philosophical approach to this, while I prefer instrumental reductionism. If a collection of “fubs” plus the rules of their behavior predict what these fubs do at any point in time, why do you need to worry about some “temporal parts”? If you take an MP3 file and a music player and press “start”, you will have music playing. If this time stuff sounds mysterious, consider Eliezer’s timeless picture, where these fubs are slices of the flow. You can generalize it somewhat to quantum things, but there will be gaps (denied by handwaving MWIers, explicit in shut-up-and-calculate), hence the probabilistic nature of it.
We share the impression that the right answer will be a reductive, empirically grounded one. We might differ on the instrumentalism part: I really do want to know what the furniture of the universe is. I have no intended use for such knowledge, and its predictive power is not so important. So far as I understand instrumentalism, you might just reply that I’m barking up the wrong tree. But in case I’m not...
But let me ask this question again directly, because I think I need an answer to understand where you’re coming from: are fubs (everyday objects like tables and chairs and people, or if you like elementary particles or whatever) reducible to processes at some level of physical explanation? Or is the whole idea of a fub incoherent? Is the question somehow incoherent? Or would you guess that when we arrive at the right physical theory, it will include reference to both processes (like decoherence, motion, heating, etc.) and fubs?
Hmm, I’m not sure how to avoid repeating myself. I’ve already said, and so has Luke_A_Somers, that “fubs” are 3d spatial slices of 4d spacetime regions. If this statement does not make sense to you, we can try to dissect it further. is there a particular part of it that is problematic?
Ah! I didn’t catch that. Thanks. Suppose a man-made satellite (Fubly 1) is released into (non-geosynchronous) orbit around the earth directly over Phoenix, Arizona. Each time it orbits the earth, it passes over Phoenix, and we can count its orbits this way. One orbit of Fubly 1 is extended in time in the sense that it takes one month (say) to get around the whole planet. In any time less than one month, the orbit is incomplete. So the orbit of Fubly 1 is temporally divisibile in the sense that if I divide it in half, I get two things neither of which is an orbit of Fubly 1, but both of which are parts of an orbit of Fubly 1.
Now, Fubly 1 itself seems different. Suppose Fubly 1 only completes one orbit and then is destroyed. Supposing it’s assembled and then immediately released, the spaciotemporal region that is Fubly 1 and the spaciotemporal region that is the orbit of Fubly 1 have the same extension in time. If I divide the spaciotemporal region of the orbit in half, time-wise, I get two halves of an orbit. If I divide the spacio-temporal region of Fubly 1 itself, I don’t get two halves of a satellite. Fubly 1 can’t be divided time-wise in the way its orbit and its lifespan can. Does that make any sense? My question, in case it does, is this ’Is the distinction I’ve just made likely to be meaningful in the correct physics, or is this a mere artifact of intuition and natural language?
It’s already the result of such a division. As for orbits and lifespans, they are not physical objects but rather logical abstractions, just like language is (as opposed to the air released from the mouth of the speaker and the pressure waves hitting the ear of the listener).
If you mean that Fubly 1 is a given 3d slice, can Fubly 1 persist through time? I mean that if we take two temporally different 3d slices (one at noon, the other at 1:00PM), would they be the same Fubly 1? I suppose if we were to call them ‘the same’ it would be in virtue of a sameness of their 3d properties, abstracted from their temporal positions.
I don’t know what sameness is, sorry. It’s not a definition I have encountered in physics, and SEP is silent on the issue, as well. I sort of understand it intuitively, but I am not sure how you formalize it. Maybe you can think about it in terms of the non-conservation of the coarse grained area around the evolved distribution function, similar to the way Eliezer discussed the Liouville theorem in his Quantum Sequence. Maybe similar areas correspond to more sameness, or something. But this is a wild speculation, I haven’t tried to work through this.
Well, thanks for discussing it, I appreciate the time you took. I’ll look over that sequence post.