counting, rationality and Homo sapiens From the perspective of the evolution of rationality, or perhaps its potential universality, it is interesting to note that recognizing numerical correspondence is not an exclusively human, or even primate, capability. Crows have demonstrated numerosity. They have the intrinsic capability to compare numerical quantities and recognize even rather abstract correspondences (eg., matching n sequential sounds to n visual objects). Whether the mechanisms used by crows and primates reflect evolutionary convergence or orthology is unclear at this point, to the best of my knowledge. In the experimental setting, ambiguities are generally minimized, this could easily be modulated. Either way, recordings from single neurons makes it clear that there is intrinsic nebulosity in the neural representation of numerical quantities - in crows and in primates - and that the neural circuitry employs error functions in making comparisons.