596 THE POPULAR SCIENCE MONTHLY. 



A THINKING MACHINE. 



By grant ALLEN. 



" T I THINGS marvelous there are many," says the Attic dramatist, 

 -1- "but among them all naught moves more truly marvelous than 

 man," And, indeed, when one begins seriously to think it over, there 

 is no machine in all the world one-half, nay one-millionth part, so ex- 

 traordinary in its mode of action as the human brain. Minutely con- 

 structed, inscrutable in all its cranks and wheels, composed of number- 

 less cells and batteries, all connected together by microscopically tiny 

 telegraphic wires, and so designed (whether by superior intelligence or 

 evolutionary art) that every portion of it answers sympathetically to 

 some fact or energy of the external universe — the human brain defies 

 the clumsy analysis of our carving-knife anatomists, and remains to 

 this day a great unknown and almost unmapped region, the terra in- 

 cognita of modern physiology. If you look into any one of the ordi- 

 nary human machines, with its spokes and cogs, its springs and levers, 

 you can see at once (at least, if you have a spark of native mechanical 

 intelligence within you) how its various portions are meant to run to- 

 gether, and what is the result, the actual work, to be ultimately got 

 out of it. But not the profoundest microscopist, not the acutest psy- 

 chologist, not the most learned physiologist on earth could possibly 

 say, by inspecting a given little bit of the central nervous mechanism 

 of humanity, why the excitation of this or that fragment of gray mat- 

 ter should give rise to the picture of a brown umbrella or the emotion 

 of jealousy, why it should rather be connected with the comprehension 

 of a mathematical problem than with the consciousness of pain or the 

 memory of a gray-haired, military-looking gentleman whom we met 

 three years ago at an hotel at Biarritz. 



Merely to state these possible alternatives of the stimulation of a 

 portion of the brain is sufficient to bring up vividly into view the enor- 

 mous and almost inconceivable complexity of that wonderful natural 

 mechanism. Imagine for a moment a machine so delicate that it is ca- 

 pable of yielding us the sensation of a strawberry-ice, the aesthetic de- 

 light of a beautiful picture, the intellectual perception of the equality 

 of the angles at the base of an isosceles triangle, the recollection of 

 what we all said and did the day we went for that picnic to the Dol- 

 gelly waterfalls, the vague and inccmsistent dissolving views of a dis- 

 turbed dream, the pain of toothache, and the delight at meeting once 

 more an old friend who has returned from India. The very mention 

 of such a complicated machinery, let alone the difficulty of its posses- 

 sion of consciousness, is enough to make the notion thus nakedly stated 

 seem wild and absurd. Yet there the machine actually is, to answer 

 bodily for its own possibility. You can not cavil at the accomplished 



