338 THE GRAMMAR OF SCIENCE 



^ 4. — The Definition of Living and Lifeless 



Now the first point to be noted is that there is no 

 single sense-impression which can be said to be that of 

 Hfe. We do, indeed, seem in our own individual cases 

 to have in consciousness a direct sense of life. But in 

 the first place we have not at present any perception of 

 consciousness except in our own individual case (p. 48), 

 and in the next place we cannot even infer that conscious- 

 ness is associated with all types of life (p. 57). We still 

 find it reasonable to speak of human beings as living 

 when they are asleep, or as living when they are com- 

 pletely paralysed ; we speak of organisms as living when 

 there is none of that hesitation between immediate sense- 

 impression and exertion which constitutes thought and is 

 the essential factor in human consciousness (p. 43). We 

 cannot, indeed, say where consciousness must be taken to 

 cease in the scale of life, but it would be ridiculous to 

 question whether fungus spores had consciousness or not 

 as a means of settling whether they were to be classified 

 as living or dead substance. The less we find exertion 

 conditioned by stored sense-impresses, the less degree 

 of consciousness can we infer. The lowliest organisms 

 appear to respond directly to their environment, and in 

 this they resemble very closely the ideal corpuscle of the 

 physicist, which dances in response to its surroundings. 

 Seeds which have been preserved for fifty or a hundred 

 years without losing their power of germination (see Ap- 

 pendix, Note IV.) are organic substance and contain life, 

 at least in a dormant form, yet it is idle here to postulate 

 consciousness as a means of classifying living and lifeless 

 organisms. 



The moment we accept without reservation the theory 

 that all life has been evolved from some simple organism, 

 then we are bound to recognise that consciousness has 

 gradually become part of life, as forms of life grow more 

 and more complex. This does not explain consciousness, 

 but it is the only consistent description we can give of 

 its evolution. The correlation of thought and conscious- 



