figurative language, he argues that the reasoning we use for such abstract topics as warfare, economics, or morality is somehow rooted in the reasoning we use for such mundane topics as spatial relationships. (See conceptual metaphor.) Finally, based on research in cognitive psychology and some investigations in the philosophy of language, he argues that very few of the categories used by humans are actually of the black-and-white type amenable to analysis in terms of necessary and sufficient conditions. On the contrary, most categories are supposed to be much more complicated and messy, just like our bodies. "We are neural beings", Lakoff states, "Our brains take their input from the rest of our bodies. What our bodies are like and how they function in the world thus structures the very concepts we can use to think. We cannot think just anything — only what our embodied brains permit." Lakoff believes consciousness to be neurally embodied, however he explicitly states that the mechanism is not just neural computation alone. Using the concept of disembodiment, Lakoff supports the physicalist approach to the afterlife. If the soul can not have any of the properties of the body, then Lakoff claims it can not feel, perceive, think, be conscious, or have a personality. If this is true, then Lakoff asks what would be the point of the afterlife? Many scientists share the belief that there are problems with falsifiability and foundation ontologies purporting to describe "what exists", to a sufficient degree of rigor to establish a reasonable method of empirical validation. But Lakoff takes this further to explain why hypotheses built with complex metaphors cannot be directly falsified. Instead, they can only be rejected based on interpretations of empirical observations guided by other complex metaphors. This is what he means when he says that falsifiability itself can never be established by any reasonable method that would not rely ultimately on a shared human bias. The bias he's referring to is the set of conceptual metaphors governing how people interpret observations. Lakoff is, with coauthors Mark Johnson and Rafael E. Núñez, one of the primary proponents of the embodied mind thesis. Lakoff discussed these themes in his 2001 Gifford Lectures at the University of Glasgow, published as The Nature and Limits of Human Understanding. Others who have written about the embodied mind include philosopher Andy Clark (See his Being There), philosopher and neurobiologists Humberto Maturana and