to push the problem back a few million years. This theory tells us nothing 

 about how living matter could have arisen in the first place. It accepts the 

 appearance of life as of one date rather than another. A further difficulty with 

 this theory is that it tells us nothing about particular forms of life. It merely 

 offers a "germ" or "spore", which in due course came to be this species and 

 that species and another species. 



We cannot harmonize what we know of the earth and its past and what we 

 know of other bodies in space with the idea that life has "always" existed, 

 nor with the idea that it came in some form from another world. 



How Can We Know about the Beginnings of Life? 



Two Distinct Questions We know that a particular robin or radish 

 came from a particular egg or seed. When we ask how life started, we raise 

 two distinct questions. 



Sometimes our question means, What is the origin of particular species — 

 horses, for example, or oaks? This question is a scientific one, for it has to do 

 with facts: When did bees first appear, or seed plants? We can compare similar 

 plants and animals from different regions. We can compare similar forms 

 that lived at different times in the past. From the facts so gathered, we can 

 infer a coherent, even if incomplete, story of events, just as the historian or 

 the detective pieces together bits of evidence into a consistent, although in- 

 complete, story of "what must have happened". We may thus reasonably 

 attempt a scientific answer to the question "How did different species arise?" 



Sometimes, however, our question as to the origin of life refers to that 

 peculiar something about all plants and animals which somehow distinguishes 

 living things from all others. This is a question about which we can speculate 

 or argue, but not one about which we can readily make experiments or observe 

 conclusive facts. The very question presupposes that life exists apart from 

 living objects or apart from matter and energy. The question is in some 

 ways like the question What becomes of the reflection in the mirror when the 

 lights go out? or What becomes of your lap when you stand up? 



Vitalism All that we know about life is what we know about living plants 

 and animals. We know that animals and plants assimilate food and grow, that 

 they respond to external disturbances by movements and by chemical changes, 

 that they reproduce themselves. We sum up what we know about millions 

 of plants and animals by saying — for convenience only — life increases in 

 amount, life responds to changes, life reproduces itself. 



We can study more closely the activities of particular living things. We 

 can then break some of the facts down into simpler and more familiar facts. 

 We can see that solution, osmosis, oxidation, evaporation, diffusion, and other 

 physical and chemical processes go on in organisms. We are confident, from 



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