2. Here are some interesting quotes by the great economists encountered in the previous chapters: The outstanding fact is the extreme precariousness of the basis of knowledge on which our estimates of prospective yield have to be made. Our knowledge of the factors which govern the yield of an investment some years hence is usually very slight and negligible. If we speak frankly, we have to admit that our basis of knowledge for estimating the yield ten years hence of a railway, a copper mine, a textile factory, the goodwill of a patent medicine, on Atlantic liner, a building in the City of London amounts to little and sometimes to nothing; or even ve years hence --John Maynard Keynes Explain Keynes's comment in light of the discussion of expected profits on page 271