Mike

“a typical chromosomal DNA molecule in a human being is composed of about five billion pairs of nucleotides… But since there are four different kinds of nucleotides, the number of bits of information in DNA is four times the number of nucleotide pairs. Thus if a single chromosome has five billion (5 X 10^9) nucleotides, it contains twenty billion (2 X 10^10) bits of information… We also see that if more than some tens of billions (several times 10^10) of bits of information are necessary for human survival, extragenetic systems will have to provide them: the rate of development of genetic systems is so slow that no source of such additional biological information can be sought in the DNA.”
― Carl Sagan, The Dragons of Eden: Speculations on the Evolution of Human Intelligence

“Pliny suggested that the ostrich, then newly discovered, was the result of a cross between a giraffe and a gnat. (It would, I suppose, have to be a female giraffe and a male gnat.) In practice there must be many such crosses which have not been
attempted because of a certain understandable lack of motivation.”
― Carl Sagan, The Dragons of Eden: Speculations on the Evolution of Human Intelligence

“Once intelligent beings achieve technology and the capacity for self-destruction of their species, the selective advantage of intelligence becomes more uncertain.”
― Carl Sagan, The Dragons of Eden: Speculations on the Evolution of Human Intelligence

“If the fact that brutes abstract not be made the distinguishing property of that sort of animal, I fear a great many of those that pass for men must be reckoned into their number.”
― Bishop Berkeley