The Appearance Of Intelligence

Philosophically, I agree with this statement by Poul Anderson in Is There Life On Other Worlds? (New York, 1963), Chapter 6, The Appearance of Intelligence:

"We cannot say flatly that [intelligent] life must exist. There is no scientific evidence that nature strives toward the goal of consciousness, or indeed toward any goal. On the contrary, the fossil record speaks strongly against such beliefs." (p. 112)

Anderson goes on to argue that, if evolution is interpreted anthropomorphically, then it consists of false starts and repeated mistakes, like overspecialization. In fact, even mankind has design flaws. Nevertheless, he reaches the conclusion that:

"Not only is life common throughout the universe, but intelligence is." (p. 118)

I had to reread pp. 112-118 carefully to follow his reasoning. Natural selection produces not only efficient microbes and insects but also organisms with:

"...increasingly better sense organs and more elaborate nervous systems." (p. 114)

Meanwhile, any ecology will sooner or later produce:

"...niches which animals with a good brain can fill." (p. 115)

Such animals, not over-specialized, are alert and adaptable enough to survive "...under many different conditions." (ibid.) Their behaviour becomes learned instead of merely inherited when chance events like climatic changes or geographical displacements prioritize brains.

Mammals, including African apes, flourished twenty five million years ago in the Miocene period on Earth. Natural selection will produce Miocene-equivalent periods elsewhere, then chance events will occur, by chance.

Anderson summarizes:

200 million years from trilobites to fish;
60 million from fish to animals;
24 million from ape to erect tool-user;
1 million more to modern man.

If whatever accidents caused the evolution of modern man had not happened in the last million years, other "...crucial events..." would be "...likely to occur..." in the next few million. (p. 117)

I agreed with Anderson's premise and was surprised by his conclusion but cannot fault his reasoning. I have learned by writing this summary.