Some people claim that human beings were created perfect, but chose evil, and that any imperfections are punishment for choosing evil. Others say that there is no clear concept of what is meant by "perfection" of a biological species, and that any species that sees itself as the high point of creation has delusions of grandeur, and an inadequate knowledge of the complicated and circuitous evolutionary pathway that led here.
(...) revolutions do bring with them an overall increase in puzzle-solving power (...)
Kuhn is quick to deny that there is any inference from such increases to improved nearness to the truth ((1962/1970a, 170–1). Indeed he later denies that any sense can be made of the notion of nearness to the truth (1970a, 206). Rather, he favours an evolutionary view of scientific progress (1962/1970a, 170–3).
The evolutionary development of an organism might be seen as its response to a challenge set by its environment. But that does not imply that there is some ideal form of the organism that it is evolving towards.
Analogously, science improves by allowing its theories to evolve in response to puzzles and progress is measured by its success in solving those puzzles; it is not measured by its progress towards to an ideal true theory.
From:
http://plato.stanford.edu/entries/thomas-kuhn/