Loren Eiseley was holder of the chair of anthropology at the University of Pennsylvania and lyrical science writer who echoed a view, expressed earlier by Alfred Russell Wallace and William Matthew, that extraterrestrial life must be morphologically diverse:¹

 

Every creature alive is the product of a unique history. The statistical probability of its precise reduplication on another planet is so small as to be meaningless.

 

References

1. Eiseley, Loren. The Immense Journey. New York: Vintage Books (1946).
2. Eiseley, Loren C. "Is Man Alone in Space?" Scientific American, 189, 80-86 (July 1953).