Natural Kinds

The world as we experience it is not a constantly changing mosaic of sensations in which no order can be discerned, but one which evinces a particular regularity from day to day and year to year. For modern science this regularity rests on the principle of the uniformity of nature, which states that natural change is lawful or takes place according to rules. In conjunction with the other two principles fundamental to modern science, it claims that changes in the world are the result of causes contiguous with their effects operating in a regular fashion on a perpetually existing substance. In this way modern science attempts to explain change in terms of non-change: perpetually existing (types of) causes operate on a perpetually existing substance in a regular manner.