Explanations in Science
What does one mean by the term explanation? This is a very complex question in the philosophy of science. It has been extensively discussed and debated by philosophies. But we shall consider it from a relatively simple point of view. To clarify the idea of explanation, let us consider the following situations:
First take the case of a child in front of a turned on TV. If the child is too little she will be totally indifferent to it. If she is a little older she may be watching the screen happily, and the question may not even arise in her mind as to how this is possible: people talking, cars moving, music playing, etc. all on front of a box. Indeed such questions don’t bother even some adults. At this stage, there can be no science at all, since a need for explanation has not been felt before there is any science.
At a slightly more advanced stage the child may begin to wonder about these matters. Now suppose that the child is old enough to ask how it is possible to see a whole band playing music on the TV screen. An adult may reply that there is in fact a live band inside of the box, and many other people and things who show up every time we turn the TV on. The child might simply say, “Oh!,” and be satisfied. As far as she is concerned the matter has been explained.
Next consider the fact that an object that is hurled into the air always falls back to the ground. We would like to explain this. Suppose we are told that everything in the neighborhood of the earth belongs to the earth, very much as children belong to their parents. And just as a child who moves away from home eventually comes back there, so too objects that move away from the earth return to the ground. This explanation is known to have satisfied many people at one time.
Finally, let us take the phenomenon of water boiling into steam when sufficiently heated. How does this happen? We may be told that the effect of heat on any substance is to change its state from solid to liquid, and from liquid to gas. Change of phase is an inevitable consequence of adding heat energy to a material substance. This explanation may also be satisfactory to many.
A scientifically literate individual will characterize the first explanation as ridiculous, the second as unscientifically simplistic, and the third as being only vocabulary-wise scientific, if at all. But what is important in any given instance is whether or not the person seeking the explanation is satisfied by the answer. If he or she is, then as far as that person is concerned, the required explanation has been found, and there is no need to continue to probe any further on this matter. One often refers to explanations as being satisfactory or not. Thus, explanation is essentially creating the impression that one understands.
The question that now arises is the following: How can one be sure that the impression of having understood a phenomenon is no more than an illusion? We can try to gain some insight into this problem by carefully analyzing the types of explanations one encounters.
Let us go back to the adult’s answer to the child concerning the TV. We may not find that explanation satisfactory at all, but the child does. This is because of two different, though interrelated, factors. First, the child is not mature enough. Her mind is as yet not developed enough to recognize the impossibility, not to say the absurdity, of the explanation offered. This is because she is not sufficiently acquainted with the world. Thus we see that two important conditions are necessary before one can give or evaluate an explanation: One is intellectual maturity, and the other is a fair degree of familiarity with the external world.
Now let us take up the second explanation considered above about why bodies fall back to the ground. This type of explanation is generally rejected by science because it is based on a worldview according to which inanimate nature also behaves like animate creatures. This point of view was quite common in ancient science, and was very successful (in the sense of being satisfactory) for many centuries. No less a person than the great thinker and philosopher Aristotleâ€”often regarded as the founder of logical thinkingâ€”propounded and adopted such a picture of the physical world.
Stephen Gaukroger called this explanatory structures. He defined the explanatory structure of a theoretical discourse as “that structure which determines what counts as an explanation in that structure.”
In most scientific explanations one tries to establish causal connections between events. In other words, one seeks to explain observed phenomena in terms of causes and effects. The notion of cause itself is a very complicated one, one on which even renowned philosophers canâ€™t agree. The idea involves intricate metaphysical subtleties. One can go into an analysis of whether a supposed cause is necessary or sufficient, whether the effect is implicitly contained in the cause, whether it is always necessary or may only occur with a certain degree of probability, and so on.
From a common sense point of view, when two events A and B always occur in conjunction, A (generally, but not necessarily) preceding B, we say that A is the cause and B is the effect. As an example of the possible simultaneity of cause and effect, the motion of the automobile may be regarded as the cause of the motion of the passenger in it. Yet both occur at the same time. This simplistic view can be logically challenged on a philosophical basis. Nevertheless, the search for causes continues in science where one makes an attempt to find interrelations between various phenomena. Once we grant or assume that natural phenomena donâ€™t occur at random or sporadically, that there is in fact an order governing the behavior of nature, we also assume that the observed events bear to one another mutual relationships, direct or indirect. These relationships are described in terms of the concept of cause. Oftentimes, the effort to explain is also a search for causes.
There is one type of so-called scientific explanation which is, in fact, a pseudo-explanation. This consists in the use of technical terms to create the illusion that something has been explained. Why are leaves green? Because, it says in a botany book, they contain chlorophyll. The uninitiated will imagine that we now have a scientific explanation for the greenness of leaves. Now any good dictionary will tell us that in Greek chloros means green, and phylon is leaf. Put in plain English, all we are saying is that leaves are green because they contain a substance that makes them green. Likewise, in answer to the question why a metal rod expands when heated one may say that this happens because metals have a positive coefficient of expansion. Why are DNA molecules so long? Because they are polymers. And so on. Unfortunately, this type of pseudo-explanation is practiced as much by innocent science-oriented people as by clever commercials whose object is to sell something on the basis of its scientific support.