Why Do We Believe What Science Says? 23 



clock A caused the striking of clock B. It is obvious that 

 our first expectation would be more or less correct if 

 nothing happened to disturb the original arrangement, but 

 our conclusion about cause would be quite wrong. Philos- 

 opher David Hume, writing at about the time of the 

 American Revolution, explored the problem very thor- 

 oughly and came to the general conclusion that there is no 

 way of being absolutely sure that one event causes another 

 or that any amount of knowledge of the past can give us 

 certain knowledge of the future. We do not have the 

 time or space to explore his interesting discussion any 

 further in this book. Those who have the inclination to 

 do so can easily read the original in Hume's Treatise 

 of Human Nature or the condensed account given by 

 Bertrand Russell in his History of Western Philosophy. 

 Incidentally, David Hume, besides being the most coura- 

 geous of philosophers, is also among the easiest and pleas- 

 antest to read — even though his conclusions are bound to 

 be upsetting to those who would still like to believe some- 

 thing with certainty. 



After reviewing all the arguments he could think of, 

 Hume states his final conclusion in his clear, earthy fash- 

 ion, "The supposition that the future resembles the past 

 is not founded on arguments of any kind, but is derived 

 entirely from habit." 



In actual practice, scientists worry very Uttle about the 

 questions we have been concerned with in the last few 

 paragraphs and which are known in learned circles as the 

 metaphysical foundations of science. They do, in fact, rely 

 entirely on habit and they are quite content to do so 

 because it works. 



Most good scientific papers these days rarely, if ever, 

 mention such words as "cause" and "effect" but the au- 

 thors merely content themselves with describing what they 



