Before language, our ancestors could form new beliefs only through what they directly experienced of the physical world around them. For perceptual beliefs from direct sensory experience, it’s reasonable to presume our senses aren’t lying. Seeing is, after all, believing. In fact, questioning what you see or hear can get you eaten. For our evolutionary ancestors, it was better to be safe than sorry, especially when considering whether to believe that rustling in the grass is a lion.As a result, we didn’t develop a high degree of skepticism when our beliefs were about things we directly experienced, especially when our lives were at stake.