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Light
Sept 26, 2012 18:34:24 GMT 1
Post by fascinating on Sept 26, 2012 18:34:24 GMT 1
Well all I am saying is that the direct experience of something is different to the knowledge about something.
Asking me what evidence I have of that is like asking what evidence I have for believing that chalk and cheese are different, from the mere fact of my looking at the properties of chalk and the properties of cheese, and declaring that they are different. I can only say that they are different on the basis of my own experience.
I think your knowledge of EEG is rather wanting. This measures brain waves coming from the movement of ions through the brain. Electromagnetic waves are not involved, not any that can be measured by an EEG anyway, and none that are at the wavelenghs at (what are called) red or blue light.
I told you about the colour blind researcher who, despite learning all about the visual system, still did not understand the concept of redness until he could subjectively experience the colour. What are your thoughts on that?
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Light
Sept 27, 2012 23:51:46 GMT 1
Post by mrsonde on Sept 27, 2012 23:51:46 GMT 1
mrsonde, my OP was as follows: "Why does blue light have high energy photons while red light has low energy photons?" Now how could this question possibly be misconstrued as one about the human visual system? Ermmm...the clue is in the terms, "red" and "blue"? They're, like, colours? Perhaps you're unaware that the current scientific consensus is that colours do not really exist - they are not an intrinsic property, as fascinating informed you, of light at all, but a product of the mind - specifically (though, admittedly, they're conveniently shoulder-shrugging about this point), the human mind. That is - colour is held to be a product of the perceptual system, highly culturally determined. Well, then, as I say, your question was tautologous. You merely asked: "Why does low-energy light consist of low-energy photons?" What else do you imagine you were asking? What is "the context" of the question then? What did you intend to ask? Fascinating answered your question by informing you about the basic cellular mechanisms of the eye, to which you responded, "thankyou". Yet you now inform us most indignantly that you were not asking in the least about the human perceptual system. So we must suppose what? How is it possible for high frequency light-waves to be distinguished from low-frequency ones? Well, there are many ways - basically you do so by some system of absorbing and thereby responding to one rather than the other. An aerial does perfectly well - in your radio for example. Does that satisfy you? I like an interesting conversation. I gave you the benefit of the doubt that you were trying to start one. I hadn't realised you were asking a question along the lines of: "Why does a square have four corners?" About light, is it? What is it about light that you wish to know, or talk about, then? You are apparently aware that it can sometimes have a relatively low energy, and that in the visible spectrum we label these differences by colour terms. What's the query beyond that? Why do we call one end of the spectrum blue and the other red, rather than the other way around - is that it? Well, let's hear your rational discussion, please. Wtf is it that you're asking?
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Light
Sept 28, 2012 0:36:32 GMT 1
Post by mrsonde on Sept 28, 2012 0:36:32 GMT 1
Well all I am saying is that the direct experience of something is different to the knowledge about something. Okay. But, generally, most of us would say that direct experience of something is what gives us the most indubitable standard of knowledge, don't we? Seeing is believing? You look at the grass and you can't doubt that it's green? Your tooth hurts and you damn well know it? Whether the Sun is 93 million miles away, on the other hand... But I take your point. As I suggested earlier, I think what you're saying is that immediate sensory experience is different from the contemplation of logico-mathematical propositions (and these are, I take your argument, a different standard of "knowledge" altogether.) Ermmm...no, that wasn't really what I was asking. I was asking what evidence you had for supposing that secondary qualities - colours, for example, in this instance - were not objectively real, but only denizens or products of the mind. Specifically, what you asserted was that colour was not an intrinsic property of light. That's what I was asking - what's the evidence for this? Does your experience tell you that colours do not exist in the world, then? No, I assure you. I've been using several of them for thirty years. No, I'm afraid not. Would that we could have access to such a delicately sensitive device! (Though, taken strictly literally, you are correct of course - the neurones are all firing thanks at least in part to their internal and external transport of ions. But what is it that you think is being measured, if not the em field generated by the movement of charge? Apart from a direct electrical connection, how else is it ever done?) The truth is - it's only very recently indeed, within the last five or so years, that anyone has really understood what an EEG measures. It's actually the mass-produced field that's detected - and it's this field that the neurones are reacting to in the first place, rather than their own internally generated electrochemical process. You follow? That is - the neurones are firing in resonance with the field. Chicken and egg a bit - but it's the mass-produced noise of the chicken that the EEG electrodes are responding to. An EEG detects the electromagnetic waves generated by many millions - billions, probably, in most EEG machines - of neurones all firing simultaneously, generating a coherent synchronised vibrating (transmitting) em field. That's all it's sensitive enough to detect, at this stage of its development. Measuring the magnetic field generated by these mass coherent em fields is easier, because body tissue as with most other materials is far more permittive to the transmission of the magnetic rather than the electric aspect of an em field, and it falls off by the square rather than the cube of the distance - you don't need to put the receiving electrodes on the skull, but can pick it up many metres away. About 20 metres has been recorded, so far. (Though you're probably aware that Michael Persinger has recorded magnetic transmission and reception of brain waves between two people considerably further, including through separating walls.) Ahhh - well, that's a separate point. The normal wavelengths that you hear talked about in relation to a typical EEG recording are at a much longer wavelength, it's true. But I assure you, that's because of the above point - the fundamental mass brain rhythms (alpha waves, delta, theta etcetera) are the result of billions of concerted neurones. Within that synchrony are a vast complex of other em waves, many also synchronous, many more more localised, down to each individual neurone. I don't know if you know how an MRI measurement works? It's merely stimulating cells in the brain - the water molecules in them, usually - artificially, in a precise pre-determined manner. But those vibrations - the ones the MRI exploits in this pre-determined stimulated manner to form exquisite pictures of the brain - are going on all the time, according to their own ongoing activity. That's not at colour frequencies either - at least, not entirely (the whole visible spectrum is certainly radiated by all our cells; though they tend to operate in the infrared, primarily: this is the preferred frequency of our mitochondria, and our Golgi apparatus - both of which are the essential engines of the ion transport you've referred to. Other systems use different spectra - DNA for example transmits and receives mainly in the UV spectrum - which is why sunlight damages it so easily.) But all that's somewhat an irrelevant point, because of a phenomenon of waves called octaves. In a nutshell, you'll identify 256 c/s as a C; and you'll identify 128 c/s as a C too, and 512...until somewhere around 40,000 Hz, when you can't hear it at all. But if you could - you'd still say, that's a C. It's just we don't notice this phenomenon of waves - all waves - as far as colours are concerned, because our eyes only register a single (well, slightly more than a single - which is why violet-magenta-mauve seems so similar) octave of light. I don't mean this as a metaphor, but literally, as a fact of physics. Luca Turin has shown the same phenomena apply to odours, in his vibrationary theory of smell (which is not really a theory any more, but demonstrated fact.) Basically, what I said. He may have understood the mechanisms of colour production. That is - the logico-mathematical description of how it came to be transmitted, etcetera. But, as you say, he would still not have understood what "redness" meant. I don't see the relevance to this discussion, though, sorry: please expound further.
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