Obdurodon tharalkooschild, an extinct species of platypus, was twice as big as its modern relatives. It lived in fresh waters where it preyed on turtle, frog, and fish. Everything we know about O. tharalkooschild is from a tooth found by paleontologists in 2012. One. Single. Tooth. Given such lack of evidence, how can we claim to know anything about its size, habits, and diet? Is knowledge even possible?

Some philosophers of science are pessimists about our prospects to learn about the deep past, of which evidence is scarce. Adrian Currie is not. In his book Rock, Bone, and Ruin, Currie makes a case for optimism; we can, and do, gain real knowledge abut the deep past.

Currie identifies three grounds for pessimism about historical investigations targeting events in the deep past:

First, our available evidence about the past is limited to traces. Historical evidence consists in material remains, and in unlucky circumstances they do not suffice to ground claims of knowledge about the events that left the remains. Second, much information from the past has degraded and disappeared. Third, historical scientists cannot manufacture evidence. Thus, pessimism is true.

Currie argues that these propositions are false. Historical scientists are not restricted to traces, but can rely on other kinds of evidence. They can utilize analogies, i.e., comparisons between historical remains and things and phenomena that we have real knowledge about. Moreover, historical scientists can explore dependencies between past variables—if a, then b—and manufacture evidence by constructing simulations and models. Pessimism is ungrounded.

However, Currie does not settle with rebutting the pessimist argument, he also provides a positive case for optimism. Historical scientists are ”methodological omnivores” in possession of a variety of epistemic resources that have enabled significant methodological and epistemic progress over the last century. That development should be expected to proceed. Historical scientists continuously adopt new methods and technologies that are likely to produce more knowledge about the deep past. Optimism is well-grounded.

Rock, Bone, and Ruin is sufficiently detailed to satisfy philosophers of science while being entertaining enough for the rest of us to enjoy it. Currie exemplifies his abstract arguments with exciting cases from the historical sciences, rendering an interesting and educative book. Philosophers of science with an interest in the historical sciences must read Rock, Bone, and Ruin. Others should read it for the mere pleasure of learning about the deep past; everyone loves platypuses, right?


Currie, A. (2018). Rock, Bone, and Ruin: An Optimist’s Guide to the Historical Sciences. The MIT Press.