THE ART OF SCIENTIFIC INVESTIGATION 



scientist and often a team. The role of reason in research is not 

 so much in exploring the frontiers of knowledge as in developing 

 the findings of the explorers. 



A type of reasoning not yet mentioned is reasoning by analogy, 

 which plays an important part in scientific thought. An analogy 

 is a resemblance between the relationship of things, rather than 

 between the things themselves. When one perceives that the 

 relationship between A and B resembles the relationship between 

 X and T on one point, and one knows that A is related to 5 in 

 various other ways, this suggests looking for similar relationships 

 between X and T. Analogy is very valuable in suggesting clues or 

 hypotheses and in helping us comprehend phenomena and 

 occurrences we cannot see. It is continually used in scientific 

 thought and language but it is as well to keep in mind that analogy 

 can often be quite misleading and of course can never prove any- 

 thing. 



Perhaps it is relevant to mention here that modem scientific 

 philosophers try to avoid the notion of cause and effect. The 

 current attitude is that scientific theories aim at describing associa- 

 tions between events without attempting to explain the relation- 

 ship as being causal. The idea of cause, as implying an inherent 

 necessity, raises philosophical difficulties and in theoretical physics 

 the idea can be abandoned with advantage as there is then no 

 longer the need to postulate a connection between the cause and 

 effect. Thus, in this view, science confines itself to description — 

 "how", not "why". 



This outlook has been developed especially in relation to 

 theoretical physics. In biology the concept of cause and effect is 

 still used in practice, but when we speak of the cause of an event 

 we are really over-simplifying a complex situation. Very many 

 factors are involved in bringing about an event but in practice we 

 commonly ignore or take for granted those that are always present 

 or well-known and single out as the cause one factor which is 

 unusual or which attracts our attention for a special reason. The 

 cause of an outbreak of plague may be regarded by the bacterio- 

 logist as the microbe he finds in the blood of the victims, by the 

 entomologist as the microbe-carrying fleas that spread the disease, 

 by the epidemiologist as the rats that escaped from the ship and 

 brought the infection into the port. 



94 



