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.[16] Others who have written about the embodied mind include philosopher Andy Clark (See his Being There), philosophers and neurobiologists Humberto Maturana and Francisco Varela and Varela's student Evan Thompson,[17] roboticists such as Rodney Brooks, Rolf Pfeifer and Tom Ziemke, the physicist David Bohm (see his Thought As A System), Ray Gibbs (see his Embodiment and Cognitive Science), John Grinder and Richard Bandler in their neuro-linguistic programming, and Julian Jaynes. The work of these writers can be traced back to earlier philosophical writings, most notably in the phenomenological tradition, such as Maurice Merleau-Ponty (1908–1961) and Heidegger (1889–1976). The basic thesis of "embodied mind" is also traceable to the American contextualist or pragmatist tradition, notably to John Dewey in such works as Art as Experience (1934).