"specifically falsifiable predictions, in the 1987 work and in "Philosophy in the Flesh" (1999) suggests that the cognitive-metaphor position has no objections to the scientific method, but instead considers the scientific method a finely developed reasoning system used to discover phenomena which are subsequently understood in terms of new conceptual metaphors (such as the metaphor of fluid motion for conducted electricity, which is described in terms of "current" "flowing" against "impedance," or the gravitational metaphor for static-electric phenomena, or the "planetary orbit" model of the atomic nucleus and electrons, as used by Niels Bohr).Further, partly in response to such criticisms, Lakoff and Rafael E. Núñez, in 2000, proposed a cognitive science of mathematics that would explain mathematics as a consequence of, not an alternative to, the human reliance on conceptual metaphor to understand abstraction in terms of basic experiential concretes.