> > > Mauro Lacy wrote: >>> Mauro Lacy wrote: >>> >>> >>>> By the way, I have a question for you, in the form of a zen koan: "We >>>> >> know the sound of two hands clapping, but what is the sound of one hand >> clapping?" We can reformulate it for the ocassion as: "We know the >> interference pattern produced by two streams of light, but what is the >> interference pattern of one stream of light?" >> >>> A diffraction pattern. >>> >> >> A diffraction pattern in a medium, and depending on that medium. That >> is, >> the effect is the result of an interaction. >> > > I don't know what you mean by this. No "medium" is required. A single > beam of light traveling through vacuum diffracts with itself (or > interferes with itself, if you prefer; it's really the same effect). > That's why lasers can never be perfectly collimated; the beam always > spreads. > > Or have you discarded the usual meaning of the word "medium" in favor of > something else?
When light is "interacting with itself", it is doing it in a medium, which is the ambit of the spreading of light. No, I haven't. A medium does not necessarily needs to be material to be, nevertheles, a medium. That which is "in between", Stephen. That is the medium. > >> >>> >>>> Or better yet: >>>> "We know the gravitational effect between two material bodies, but >>>> what >>>> >> is the gravitational effect of one material body?" >> >>> Curves the metric. >>> >>> But without any other body in the universe there's nobody there to >>> >> measure it. >> >> So, an effect again arises as a result of an interaction. >> >> >>> If a tree falls in a forest and there's nobody there to hear it, does >>> it >>> >> make a sound? >> >>> Same question wearing different clothes. In both cases it's just >>> >> semantic games with an undefined term. In the question regarding the >> tree, the phrase "make a sound" was never defined and so the issue >> appears debatable. In your example, the word "effect" was never >> defined, and so the question appears debatable. >> >> The question is debatable. Although only semantically, if you like. If >> you >> define sound as "something audible" then it only occurs when someone >> hears >> it, by definition. But if you define "sound" as something that has the >> possibility of being audible, then there's sound even when nobody hears >> it, again by definition. And this is the right way to define it, IMO, >> because if not, you're left in the dark regarding the real nature of >> things. The specific phenomena of sound manifests when somebody hears >> it, >> but while nobody is hearing it, there's something there that, when >> someone >> heards it, manifests itself as sound. >> >> But I was pointing to another direction: trying to show that the >> specific >> form of things we perceive or phenomena that occurs in the world, are >> the >> result of an interaction. >> > > Obviously. That's the heart of the Copenhagen interpretation of quantum > mechanics: The observer is part of the system, and the act of observing > is an interaction. Without the presence of the observer, it's a > different system. Yes, but I was extending the interpretation, to interaction between massive bodies mediated by gravity, not only to the subject-object relationship of quantum mechanics. Incidentally, that subject-object relationship arises because observers and observational apparatus are made of the same substance than the experiments, i.e. they are interacting and this interaction is suddenly meaningful and important due to a scale factor. > >> In the same venue, gravity only makes sense as a result of the >> interaction >> of two or more massive bodies. > > What does it mean for something to "make sense"? Without a precise > definition of that phrase the sentence is meaningless. Refer to your previous example: does it make sense to talk about gravity when there's only one massive object in the Universe? It only makes sense when two or more bodies are interacting, and what I'm saying here is: it makes sense not only in a semantical way, as is the case with sound, but also on a phenomenological way, because gravity(the behaviour of gravity) is the result of that interaction, in the form of a standing longitudinal wave and its effects. > > For that matter, you haven't said what *you* mean by "interaction" or > "massive" or "body". Is a photon "massive"? Is a neutron star one > body, or is it a whole bunch of bodies, one for each neutron? My idea is that the macroscopical effects are the result of the accumulation of microscopical ones. > Does a > ray of light which is bent by a massive star constitute an "interaction" > of that star with another "massive body", or not? It constitutes it. A bent photon is the result of an interaction between the massive part of a ray of light(its longitudinal component) and the gravity of a star(the longitudinal component of the star's own light rays). This interaction is very subtle, but existent. > > Everything is debatable when nothing is defined. > > >> In a sense, gravity phenomenologically IS >> the result of that interaction, that is, gravity is different when >> there's >> an interaction, > > This sounds kind of meaningless, frankly. "Different" how? What do you > mean by an "interaction"? I meant that when gravity is not interacting with something(another massive body), it propagates in a different way that when it's interacting with other massive body(standing waves form, and the action of these standing waves is felt like "attraction"). > > More fun with undefined terms. > >> to when there's none, and that difference depends also on >> the interacting bodies, in the same way as a diffraction pattern depends >> on the medium, > > No it doesn't, as I already pointed out. > See above. There's no propagation without a "medium". If there's no "medium"(in between) there can be no propagation.
