SECTION 3. THE SCIENTIFICALLY UNTRAINED ADULT. 25 



of memories, and the possible number of associations becomes 

 therefore limitless. Consequently, especially with the priceless 

 aid of language, the process of deliberating, of reflecting, of 

 reasoning, steadily develops with experience and with guidance, 

 and in this particular respect there is, accordingly, a notable 

 distinction between the younger child and the average adult. 

 Still, the deviation, if we omit the earliest stages, is much less 

 clear between adult and child so far as the processes of in- 

 tellection are concerned, for, although the half-trained adult 

 will neither mistake the almonds on a cake for pebbles nor 

 assert that the chair is naughty, his cogitations only very 

 remotely suggest modern scientific procedure at its best. 



The average man to-day labours under peculiar disadvantages 

 from which the man of science is exempt. The latter does not 

 grudge the expenditure of the time and energy requisite for 

 solving a problem, and, what is more, if no tangible solution 

 is forthcoming, as in Faraday's attempt to detect a relation 

 between gravity and other natural forces, he merely postpones 

 or abandons the search for an explanation. The average man, 

 on the contrary, is compelled to settle every day numerous 

 problems, and he is, therefore, little perturbed when any of 

 his ordinary solutions prove partially or wholly erroneous. 



To generalise is a matter of mental economy both in practi- 

 cal life and in science, and in practical life economy is of such 

 moment that probability quickly reached is more prized than 

 certainty attained as the reward of protracted labours. The 

 average adult, no doubt, generalises excessively; but, on the 

 other hand, mere cautiousness is of doubtful positive value. 

 In certain strata of society "I think", "It appears to me", 

 "I don't know", are expressions in constant use. Precipitate 

 generalising is avoided here; but mechanical caution neither 

 dispels error nor extends the horizon of knowledge. In the 

 keen struggle for existence much must be staked, and indeci- 

 sion will not feed, clothe, house, or enlighten mankind. 



Consider an instance of every-day problems. The train by 

 which a person travels to town has been occasionally late. 

 That person, if he desired to be precise in recording the fact, 

 would need to state the number of times the train has or has 

 not been late; the dates, the hours of the day, and any special 

 circumstances which might account for the tardy arrival of the 

 trains. Rather than conduct such an elaborate investigation, 

 he would prefer to proffer no statement at all, and yet a purely 

 negative attitude on all dubious points would tend towards a 

 mental standstill. Aware of these obstacles, we are satisfied 

 in daily life with probabilities, and we seldom strive to attain 

 to even approximate certainty. What, then, is the current 

 measure of the degree of probability? The question is em- 

 barrassing. Not a few individuals universalise in an extra- 

 vagant manner. If, for instance, a train chances to be late, 



