Abstract

The empirical evidence often justifies belief in scientific theories. For instance, the great wealth of chemical and other relevant data leaves us with no real alternative to believing that matter is made of atoms. Similarly, the natural history of past and present organisms makes it irrational to deny that life on earth has evolved from a common ancestry. Again, the character and epidemiology of infectious diseases effectively establishes that they are caused by microbes. Peter Lipton did much to illuminate the logic of these and many similar inferences. Often the observed facts admit of only one good theoretical explanation. Rationality therefore dictates that we infer the truth of this explanation.