516 INTRODUCTION TO EVOLUTION 



far from proved. My own "hunch" is that all organic evolution is following 

 a pattern which constitutes one portion of the great design of the universe. 

 Of course, I cannot prove that such is the case, any more than those who 

 hold the opposite view can prove their position. 



A word seems appropriate at this point concerning the statement some- 

 times made that the universe and everything in it arose by chance. The 

 statement usually carries the implication that if a thing occurs by chance it 

 obeys no laws, follows no design, whatsoever. As should be clear to you 

 from our previous discussions, such an implication reveals a fundamental 

 misunderstanding of the nature of chance. Chance itself follows statistical 

 laws — the laws of probability which we saw to be so fundamental in 

 MendeUan inheritance (pp. 376-389), in population genetics (i.e., Hardy- 

 Weinberg law, pp. 43 1-435 ) , and hence in evolution. These laws are clearly 

 as much a part of the design of the universe as is the law of gravitation. 

 They express the regularities with which phenomena occur. Probable 

 events occur frequently, less probable events occur less frequently. But 

 even highly improbable events do occur. We are told, for example, that on 

 a roulette wheel at Monte Carlo red once came up thirty-two times in a 

 row. The probability of such an occurrence is about one in four billion. 

 Yet this high degree of improbability did not prevent the occurrence 

 from happening. Similarly, some new evolutionary developments may 

 have been dependent on very "improbable" combinations of genes and 

 mutations. It was doubtless "improbable" that a climbing or gliding insec- 

 tivore would become possessed of limb structure suitable for flight (pp. 

 504-506). Yet, as with the roulette wheel, the improbable event did occur, 

 and having occurred altered all subsequent evolutionary history of the 

 group by making possible the origin of bats. 



We should note that the occurrence of highly improbable phenomena is 

 not a "breaking" of the laws of chance. The laws of chance provide for im- 

 probable phenomena as well as for probable ones, and even predict the 

 frequency with which improbable events may be expected. 



I suspect that one reason some people doubt the existence of a design or 

 pattern in the universe, and all of us discern the pattern so dimly, if at all, 

 is because we are part of it. If we imagine a dab of paint on a canvas en- 

 dowed with the sense of sight, we readily appreciate that this bit of paint 

 would find it well-nigh impossible to see the painted landscape of which it 

 was a minute part. It might well deny that it was part of any landscape, any 

 design, at all! 



Not only is our perspective likely to be faulty; our knowledge and under- 

 standing of the universe are strictly limited by the nature of our sensory 



