8 August, 2006
Posted by: manojtd on 08/08/06 at 12:56 PM
I don’t understand why you have picked on the speed of light .
In order to understand the importance of light in our space and time, let’s consider a different space-time for instance, one created by echolocation. It’s not difficult to work out how the (blind) bat would perceive moving bodies. It turns out that the bat will think that nothing can move faster than the speed of sound. (A supersonic object moving away from the bat can never be sensed because the sound the bat emits will never reach the object, and there will be no reflection. An approaching supersonic object will pass the bat before the reflected sound reaches it, and will become a receding object.) It can also be shown that there will be a time dilation and length contraction in echolocation as predicted in special relativity (SR), again with the speed of light replaced with that of sound. Now, if the bat were intelligent enough to theorize about space and time, the theory it would have come up with would have been uncannily similar to SR with the speed of light replaced with that of sound. In this case, we can clearly see that the bat is making a theory about its perceived reality because we know what the underlying absolute reality is — it is the reality as we (humans) sense it using a faster mode (light).
It stands to reason that our space-time also must have perceptual effects. We can either attribute the effect that the finite speed of light has in our perception of moving bodies to the properties of space and time (as in SR), or we can try to “take them out” from our perception of motion. It turns out that we cannot take them out because multiple configurations can result in the same perception; it is an ill-posed problem with many valid solutions. The next best thing we can do (that I could think of) was to work forward; ie, guess a configuration and work out how we would perceive it, much like I did in the case of echolocation. I considered a hypothetical superluminal object and worked out in detail what our perception of it would be. The “luminal boom” it creates explains neatly many of the puzzling features of a Gamma Ray Burst (GRB) including the time evolution of the afterglow. The aftermath of the luminal boom (asymptotically low frequencies) explains the spectra, the observed symmetry and other time/angle dependent features of radio sources (DRAGNs). I made some predictions about their kinematics, verified some of them with existing data. I also provided some other predictions, which, if observed, will falsify my model. (Because if a model cannot be falsified, it’s no model at all.) For instance, a clear movement in the angular position of the core of a DRAGN (which would be the position of the so-called host galaxy) would invalidate my model. Or, the appearance of a superluminal “knot” in one of the jets with no counterpart in the opposing jet will also prove that my model is wrong. I can point you to my article (which I optimistically called a journal article) if you are interested in the technical details.
Despite the success of my model in describing these phenomena, it is still a tough sell because the current belief is that SR applies to the absolute reality. In other words, once you take out the light travel time (LT) effects that I described in the preceding paragraph, what is left is the space-time that is assumed to obey SR. It is an understandable assumption because, frankly, the LT effects are not that hard to work out, and it is not conceivable that the great minds of the last century didn’t work them out and see their implications. The only explanation I can think of is that they were kind of blinded by the assumption that our perceived reality was the absolute reality, and that their theories applied to the absolute reality. (Is this one way of describing scientific realism?) The real point that I’m trying to make is that SR applies to our phenomenal reality, not to its noumenal causes. This is a philosophical stance, and physics journals are not ready (perhaps rightly) to just take my word for it 
Looking at it philosophically, one can say that there is a noumenal reality of which our phenomenal perception is all based on light. Furthermore, our cognitive model for the phenomenal reality is space. Space is a cognitive representation of the photons falling on our retina, much like sound is a representation of pressure waves in the air, temperature is a model for molecular movements and smell is a model for chemical concentrations. We cannot imagine space to be a model only because we have no “higher” sense modality, and a consequent model, to understand it, which we did in the case of sound, smell and temperature. Given that space is created out of light input, it becomes immediately obvious why the speed of light is a fundamental property of our perception of space. So clearly, light and its speed are the most important things in our reality. What do you think?
The noumenal-phenomenal distinction sits well with the Eastern spiritual philosophies such as Zen and Vedanta. It’s also interesting that the Bible and Quran mention light at a very fundamental level. The first thing that the Biblical God said was “Let there be light.” Quran’s God (Allah) is described as the light of heaven and earth. My respect for these lines of thought is more like a suspicion that what they meant in their teachings is what I described above. An atheist myself, I have no real use for the mystical, spiritual side of their teachings. However, if they did know what we are only beginning to discover, then we should pay more attention to them so that we may uncover some other useful insights.
When it comes to the relevance of ancient teachings in modern sciences, there is quite a bit more to it than what I can post here (related to neuroscience, evolutionarly biology, etc.); after all, I wrote a full-legnth book about it 🙂
I wrote this at work where I couldn’t see your message. I will probably post one more message replying to some of the points you raised.
– cheers,
– Manoj