All of us vary in each of the 5 dimensions, just like we do with weight, height, or intelligence. Nettle posits that if we could measure people with ten distinct points along each of the five personality scales, there’d be 105, or 100,000 possible personalities. So even though life would be much simpler if we could wedge everyone into a few categories, we’d be wearing blinders to the true complexity of our fellow human beings.