Hej,
No I am not absolutely sure that this is me typing. But to prevent situations like Eddie describes, I assume it is me.
That is what we, humans, do, we assume things to make things understandable.
In the ancient days people assumed volcanoes erupted because of the wrath of a god. Nowadays we assume that it has to do with magma and movements of the magma.
We don't know things, we assume things and we can belief those things are truth and we can have faith that they are truth. But we cannot know if they are truth.