428 HERMANN VON HELMHOLTZ 



In giving a more exact definition of the views of Nativism and 

 Empiricism, which he had stated fifty years ago, he illustrates 

 his position by the example of a man learning a new language. 

 Here the frequent repetition of similar experiences teaches us 

 to recognize and establish a regularly recurrent association 

 between two different perceptions, which at the outset had no 

 natural relation to each other. An association between two 

 observed facts recurs with the fewest exceptions when it ensues 

 in obedience to a natural law, which requires either the co- 

 incidence or the regular sequence of the association in a given 

 interval. He returns in detail to the antithesis previously stated 

 between the cognition of an object, by means of which we retain 

 a conceptual image derived from sensory impressions, and that 

 knowledge of it which can be expressed in words, and illustrates 

 this contrast by divers examples from physiological optics. After 

 an exact definition of the concepts, intuition and thought, he 

 reverts naturally to his far earlier theory of inductive inferences 

 and unconscious inferences, and then passes to fallacious induc- 

 tions and sensory illusions, with some interesting comments 

 upon the degree of illusion, in which from the very outset he 

 makes the concept of attention play an important part. 



' I think I may sum up the preceding considerations and 

 experiences as follows : 



' i. As the evidence of innate organization in man, we find 

 reflex motions and instincts, the latter presenting the antithesis 

 of pleasure in certain impressions, pain in others. 



'2. Inductive inferences, as acquired by the unconscious 

 work of memory, play a prominent part in the building up of 

 concepts. 



'3. It seems doubtful whether the ideation of adults includes 

 any forms of cognition not derived from these sources.' 



On July n, his mind was still in full vigour. He had pre- 

 viously (on May 12) recommended Lipschitz and Konigsberger 

 to the President of the Peter- Wilhelm-M tiller Institute, Hen- 

 August Muller, of Frankfurt-a.-M., as judges in the distribution 

 of a prize of 15,000 marks, and he now wrote to the author: 



'May I suggest that the prize be given to Heinrich Hertz, who 

 died at the commencement of this year. I think all our con- 

 temporaries will agree as to the value of his discoveries and 

 their scientific results. The circumstance of his death does not, 



