The ways of Divine knowledge are not at all graspable by man.
And this, among other things, is what causes great suffering to man.
We are born small, too small to express anything, and in the process of learning to express thoughts, we become overwhelmed by words, by the influence of environment and circumstances, so that we no longer distinguish the authentic.
People learn to experience things as a result of outside forces, ideas, people, and so on.
Historically speaking, we know that prior to the adoption of certain concepts, like that of a nation, for instance, people were unable to feel anything that corresponded to such categories.
Many such notions, introduced from outside the reality of life, became an intrinsic part of the personality.
The only knowledge of which a person can be said to be sure of is that of himself, simply, a knowledge of oneself, even if this is greatly obscured by the image projected by the world.
From The Sustaining Utterance By Rabbi Adin Steinsaltz