HOW AND WHY

One thing which many people seek, and science is especially effective at finding, is knowledge of what things there are in the world, how they are related to one another, what things have happened, and when. For a long time it was not certain how long there had been human inhabitants on earth. Aristotle thought there had been humans on earth for millions of years – in fact, for an indefinite, even an infinite, expanse of time stretching into the past. The Hebrew, Christian, and Islamic traditions taught, in contrast, that there have been humans on earth for only a few thousand years. Geologists a few hundred years ago established that the mountains and oceans of the earth are hundreds of millions of years old, whereas human life has existed on earth for a much shorter time. Science has discovered how old the earth is and how young humanity is.

Enquiries of this sort are of the greatest importance and interest, and constitute an essential and substantial component of science. Yet there are also elements of science which are somewhat different. The acquisition of knowledge of what happens, where and when, is sometimes characterized as being concerned with description rather than explanation. Science, however, is concerned with both description and explanation. Yet it is misleading to draw a sharp line between description and explanation. Description and explanation are not mutually exclusive categories. It is better to distinguish among kinds of explanation.