 Clark and Chalmers (1997) motivated the extended mind thesis using a thought experiment centring upon memory. Its protagonists, Otto and Inga, each need to remember how to get to MOMA for an exhibition. Inga has been to MOMA many times and gets there via introspective recall. But Otto has an impaired capacity to produce, store and retrieve memories. To cope with this, he carries a notebook containing important information. Otto routinely consults and updates his notebook, he always carries it with him, and he endorses its contents. A variant of this view holds that agents are typically embedded in wider set of environmental and social phenomena, and that these exogenous factors are explanatorily vital and often neglected when it comes to cognition, but that cognition is intra-cranial.