Science and Morals 197 



Two principal differences distinguish the scientist's ap- 

 proach to moral values from traditional attitudes. In the 

 first place, he has more difficulty in being sure that some- 

 thing is either absolutely good or absolutely bad. In the 

 second place, he is beginning to discover and define moral 

 problems that nobody ever thought of before, or at best 

 thought of only very casually. 



The scientist's difficulty in being absolutely sure about 

 values stems in part from his general difficulty in being sure 

 about anything. As Alfred North Whitehead has said, 

 "There are no whole truths; all truths are half-truths. It is try- 

 ing to treat them as whole truths that plays the devil." ^ We 

 have already seen that sad experience has taught the scien- 

 tist that the accumulation of new evidence may upset his 

 most strongly held views on the nature of things. An even 

 greater difficulty comes from his observation that the value 

 of things varies with circumstances. This so-called rela- 

 tivity of knowledge is characteristic even of basic physics, 

 but a few biological examples may be easier to understand. 

 At the very simplest level we may consider a species of 

 animals which has developed a heavy coat of hair or fur. 

 Such animals are well adapted to life in cold cHmates but 

 do rather badly in the tropics. In value terms, hair may 

 be defined as good in one place but bad in another. We 

 now know that the value of certain human traits varies in 

 the same way with environment. A particularly interesting 

 example, which has been thoroughly studied from the medi- 

 cal, genetic, and chemical points of view, is a disease known 

 as sickle cell anemia. This is a genetic disorder which re- 

 sults in the production of hemoglobin of a slightly abnormal 

 composition. Children who inherit the disorder from one 

 parent have a very slight tendency to develop anemia but 

 are much less likely than normal people to develop severe 

 malaria. People who inherit the controlling genes from 



