The Patriarchs were able to experience the next world in this life, which we acknowledge as fact in the Grace after meals:
"May we be blessed as were our forefathers in everything and by everything."
This latter phrase points to a state of being that manifests the great gift of knowing God's presence within oneself.
The ordinary person's vision is blocked by the physicality of his own existence.
To achieve anything spiritually meaningful, a person has to have reached a certain rung or level of consciousness beyond the physical.
Otherwise, there is simply no possibility of making the contact that could enable one to understand what he is experiencing.
Just as children, and even many adults, can grasp only so much of a work of art and no more, especially if they are untrained.
They can come into physical proximity with it, see or hear it, and respond according to their individual levels of understanding.
Just as recent experiments on the process of observation in animals disclosed that they distinguish only moving objects.
Not that an animal fails to see an object that doesn't move, it is simply alerted only by the exterior stimulus.
And so it is for all creatures; the ability to grasp the reality of a situation depends on the level of consciousness of the one experiencing it.
–Rabbi Adin Steinsaltz
From The Long Shorter Way, Chapter 47, by Rabbi Adin Steinsaltz