In "The Bear," Faulkner makes a distinction between foolhardiness and bravery that relates to comprehension, reasonableness and wisdom. In Part II, the narrator is talking about the protagonist's "mongrel" "fyce" dog, saying that its hunting had long since ceased to be acts of bravery and had become acts of foolhardiness.
The distinction inferred is that it is reasonableness; comprehension of danger and reward; and wisdom in cautiousness that separates bravery from foolhardiness, which is the reckless plunging headlong into danger for the emotional thrill of it.
In another section, Faulkner suggests that the distinction between cowardice and bravery is the presence of the psychological state of fear in the former and the presence of the emotion of being scared in the latter. Here, foolhardiness seems to be distinguished from bravery by reckless, abandoned emotion as opposed to contained emotion.