(published in the Mensa International Journal, No. 339, Sep 1990)
According to the crucial postulate in Einstein’s Special Theory of Relativity, the speed of light is always constant relative to all freely-moving observers. This means, for example, that if you measure the speed of a light ray to be 300,000 kilometers per second while on Earth, an observer in a rocket travelling from Earth at, say, 150,000 kilometers per second in the same direction will also measure the same light ray to be travelling at 300,000 kilometers per second relative to him! In order for this to be possible, time and space have to be modified for each different observer in a rather complicated manner. No reason, however, has ever been given for the constancy of the speed of light, it being merely considered as a fundamental law of nature.
I propose now to present the reason for this phenomenon. In a sentence: The constancy of the speed of light is due to a limitation in man’s perceptual ability.
This may, perhaps, be best explained with an analogy: In order to measure the speed of a river flow, we place a buoy on it as a marker and determine the distance it travels. We then divide this distance by the elapsed time to obtain the speed. Suppose, unconventionally, we decide to measure time by the number of turns of a waterwheel placed on the same river, i.e., we define one unit of time by one turn of the waterwheel. If the rate at which the buoy travels and the rate at which the waterwheel turns are proportional to the rate of the river flow, we will now always measure the speed of the river flow as constant. The reason for this is that the waterwheel turns correspondingly faster whenever the river flows faster, so we cannot detect the change if we keep to our unconventional way of defining time.
Essentially, this is also the reason why the speed of light is always measured by man to be constant. We have arbitrarily defined time as the rate of electromagnetic transmission in our perceived space. (Light is a form of electromagnetic transmission.) There is, therefore, actually a limitation in our ability to measure the speed of electromagnetic transmission itself, including the speed of light.
It remains, now, to show that man has actually defined time this way. Electrical clocks and mechanical clocks not utilizing gravity clearly employ the rate of electromagnetic phenomena to measure time. (Their mechanical effects are ultimately due to electromagnetic forces.)
However, to really understand why man has arbitrarily defined time using the rate of electromagnetic phenomena, we must examine how he physiologically experiences time. Here, it is essential to realize that the human body functions like a machine and that man’s physiological processes are governed by the same physical phenomena that exist in the world around him. At the level of functioning which involves the processes whereby man perceives or experiences the universe, electromagnetic phenomena are undoubtedly the main controlling mechanism. For example, neural transmission, muscular contraction and cellular metabolism are all mediated by electromagnetic interactions. Therefore the rate of electromagnetic interactions, which is dependent on the rate of electromagnetic transmission, determines the rate of all our thought processes and bodily functions. It is hardly surprising then that man has inadvertently defined time via electromagnetism.
It should be apparent now that man does have a limitation in his perceptual ability towards the rate of electromagnetic transmission. There is simply no standard available to compare the rate of electromagnetic phenomena with, as not even our own physiological or mental processes can be used as such. In a situation similar to the analogy involving the waterwheel, we are unable to detect any difference in the rate of electromagnetic transmission because we have used it to define our time.
It may be argued, though, that man also measures time using other phenomena – for example, the rate of radioactive decay, the rate at which the Earth moves around the Sun, etc. However, this does not alter the basic logic behind the reason why the speed of light is constant.
To see this, let us return to our analogy: Suppose, now, that we wish to use an anemometer on the river bank, instead of the waterwheel, to measure time. We must, however, first ensure that both these instruments run at proportional rates. Otherwise, we cannot use the anemometer to measure the time we have already defined using the waterwheel. If an experiment does confirm that the anemometer rotates at proportional rates with the waterwheel, we may substitute the anemometer as the time-measuring instrument. We will still find, however, that the speed of the river flow is constant.
Similarly, in the real situation, we may use other phenomena, like the rate of radioactive decay, to measure time because we have already determined that they run at proportional rates to electromagnetic phenomena. Obviously, it will make no difference to our measurement of the speed of light. By his arbitrary definition of time, man has in fact also arbitrarily defined the speed of light to be constant.
The reason for the constancy of the speed of light has, essentially, been explained in this article. The true situation, however, is more complicated, but only because in addition to time, space is also defined by electromagnetic phenomena. A full discussion of this can be found in the author’s book Time and Space (ISBN 981-00-1134-2, Nov 1988), which is the original scientific treatise on which this article is based.