What can we know about that which we cannot even imagine?

It is often argued that the underlying reason for this aversion to thinking is to reduce the associated fitness costs [15, 108]. Indeed, such costs to thinking are not difficult to find. In particular, it turns out that brains are extraordinarily expensive metabolically on a per-unit-mass basis, far more than almost all other organs (the heart and liver being the sole exceptions -- see [29, 108, 79, 16]). Consistent with this, it is not just that the software comprising our minds that seems tailored to reduce metabolic costs; the hardware supporting that software -- the physical architecture of our brains -- also seems tailored to reduce metabolic costs. We do not have a good understanding of exactly how our hardware is used to provide the ability of humans to engage in activities requiring high levels of abstract intelligence.