Mental modelling explains everything your do within your mind, using an incredibly restricted set of mental assets. Three, in fact. Even more incredibly, those three components are just the conceptual expression of an even simpler underlying two-piece toolkit, namely nodes, and the connections between them. That's a good thing, because in the real world, that's pretty much all your brain's got to work with.
How is it possible that the apparent complexity of a human mind can spring from such simple components? You might as well ask how the vast range of lifeforms on the planet can spring from the four letter alphabet that comprises all DNA. It's possible to assemble any amount of complexity by layering, and all you really require at any specific level is the yes, and the no.
Rene Descartes, demonstrating (for a Frenchman) an uncharacteristically spartan turn of phrase, coined the expression "I think therefore I am", or 'cogito ergo sum' if you're Stephen Fry. It begs the question, of course, as to how 'thinking' is defined, which is no longer a problem, because we can also define that activity in terms of mental modelling. All the various forms of thinking, from simple replaying upwards, are underpinned by a single modelling activity; an activity humans indulge in to a level the rest of the animal kingdom can't begin to approach.
Intelligence per se, of course, as demonstrated by numerous other species, only requires the ability to create models. It's therefore probably incorrect to claim, as the meme says, that "I model therefore I am"; a more accurate version would be "I model my own models, therefore I am". It wouldn't be so amusing though, so I'll leave Zoolander up there, pouting for posterity.I model, therefore I am. But not in the 'Zoolander' sense. Click To Tweet