Until we reach a certain stage in the evolution/expansion of our consciousness, we have no enduring perception that there is anything more to life than material existence and our thoughts, feelings and imagination.
This is the common and 'normal' consciousness state of humanity.
Then one day, without warning, we get the first glimpse.
It can come in any number of ways.
It is a distinct coming into awareness of something the mind cannot make sense of.
This is actually the very first point when our consciousness has expanded enough to take in something that was always there.
It is like when driving in a dense fog and suddenly the headlights penetrate further through a clearer patch, revealing a little more of the road ahead.