14 THE UNFATHOMED UNIVERSE 



science of his day could not offer any explanation of the 

 origin of life, the apparent purposiveness of Nature, and the 

 origin of language; but he did not hold that these enigmas 

 were insoluble. On the other hand, as to the essence of 

 matter and energy, the origin of motion, the fact of sensa- 

 tion, and the freedom of the will, his pronouncement was 

 not only Ignoramus, but Ignorabimus. Similarly to-day, 

 without ceasing for a moment to admire the splendour of 

 scientific achievement, and the promise that there is of fur- 

 ther conquests, we have to say many times Ignoramus, and 

 perhaps it is no bad sign of the wholesomeness of modern 

 science that it is acutely aware of its limitations both in- 

 trinsic and extrinsic. 



(a) To begin with, there is less forgetfulness of the 

 fact that we know Nature only as it is mirrored in our 

 minds. When we think of what science would have been if 

 the stars had been always hidden in cloud, we realise that 

 much has depended on the stimuli of the outer world; but 

 the discernment of the cosmos has been within us, growing 

 with our strength and hindered by our limitations. It is a 

 familiar experience, for instance, that our immediate per- 

 ceptual power increases at compound interest, the eye per- 

 ceiving more and more as the mind is educated. Our 

 concepts stimulate our perceptual powers to a higher degree 

 of intensity. 



(6) A large part of even the near at hand world is 

 invisible, like the air. Much may escape all our senses, 

 as the ultra-violet rays, which the ants feel, escape our 

 eyes. It is said that there are living creatures, the Chlamy- 

 dozoa, which lie just on the border-line of microscopic 

 visibility; and beyond these minima sensibilia there may be 

 organisms still smaller. An alien observer of the earth in 



