Thomas Suddendorf (2013)
"I do not think it is useful to resurrect Darwin’s blanket statement that differences in mind between humans and animals certainly are one of degree and not of kind. The picture is more complicated. Even when we find evidence for apparent differences in degree, this need not rule out that differences in kind are also entailed: as temperature gradually increases, the properties of H2O change in kind as it transforms from a solid, to a liquid, to a gas. By the same token, continuous increase in, say, working memory capacity, may well lead to discontinuous changes in what a mind can possibly conceive of. I see no reason why mental time travel should not have evolved gradually through Darwinian descent with modification. However, continuity over evolutionary time (e.g., from Australopithecines to Homo) should not be confused with a need to postulate an absence of gaps in the distribution of traits among extant species . As transitional forms go extinct, vast qualitative differences can certainly emerge. On current evidence, it still appears that human mental time travel is profoundly special. There are few signs that animals act with the flexible foresight that is so characteristic of humans."