There's an old joke, usually told about specialists in three different sciences, that I will tell this way:
An American professor of logic is vacationing in Scotland with his wife and young son. The train they're taking passes a field in which a sheep is grazing. The boy says, "Mommy! Daddy! In Scotland, the sheep are black!"
His mother, having lived with her husband long enough to pick up some of his ways, says, "Now, honey, all we really know is that that one sheep is black."
"Actually, my dear," the professor says, "all we know is that that one sheep is black on one side."
If we think of the actions of another as the sheep population of Scotland -- and, really, how can we not? -- then, for the vast majority of others, the one side of that one sheep corresponds to their actions visible to us. What they do that we don't see is as unknown to us as the rest of the Scottish sheep are to the American family.
Obviously, it's reasonable to say that a sheep black on one side is black on the other. It's even reasonable to suppose that, where there's one black sheep, there may be more. But beyond what no one would reasonably deny, and beyond what many would reasonably suppose, there's a great deal that is unknown to us. Even the presumption of charity shouldn't lock us into a firm opinion about the truth of what we don't know.