To know-to be aware of through inquiry, observation, or information
To believe- to trust, to have confidence in, to consider truthful
I suspect most would respond to this title question by saying yes. But if we consider the above definitions, I think we see there is ample room to be aware of something without having confidence in or trusting what is known. This contrast helps explain all the political rhetoric about “fake news” and “alternative facts”, coming from all across the political spectrum. No one is really obliged to believe anything they don’t want to believe; so, in this sense, there is no absolute truth for any of us. We routinely accept or reject what we know because it either reinforces or runs counter to our opinions or our desired outcomes.
This is not a fault or shortcoming of the liberals or conservatives alone. It is a simple fact of human nature.
The old adage says there are none so blind as they who will not see. I suspect a more accurate understanding would be that even if we see it, we still don’t have to believe, unless we choose to.
Choosing to believe something new generally requires a lot of pain as the motivating force. The old belief has to become too painful to retain. If the belief has been long held and largely cherished, the level of pain required to bring about a change must be high indeed.
This same thing happens in our religious beliefs. It is easy to believe in hellfire and the sinfulness of divorce and drug addiction until it impacts someone we love. Then there is a great incentive to believe something new.
Many a religious leader will insist that the truth is not altered by its inconvenience to our personal situation. But, as noted above, what anyone believes, including the preacher, is a personal choice. The evidence be damned if I don’t want to believe it.