At one time, "Precambrian rabbits" or "fossil rabbits" or "fossil rabbits in the Precambrian" rock samples became popular imagery in debates about the validity of the theory of evolution and the scientific field of evolutionary biology. The images are reported to have been among responses given by the biologist, J.B.S. Haldane, when he was asked what evidence could destroy his confidence in the theory and the field of study. Many of his statements about his scientific research were popularized in his lifetime.
Some accounts use this response to rebut claims that the theory of evolution is not falsifiable by any empirical evidence. This followed an assertion by philosopher, Karl Popper, who had proposed that falsifiability is an essential feature of a scientific theory. Popper also expressed doubts about the scientific status of evolutionary theory, although he later concluded that the field of study was genuinely scientific.