Humans tend to think and believe that they acquire knowledge from their conditioning and experiences of the world and that such knowledge then gives them some form of vision, from which desires are created and actions are taken to gain some form of achievement.
Such knowledge of experience is merely intellectual knowledge and even though intellectual knowledge may have some value along the journey of life, at some point such knowledge will stop serving you and effectively have no meaning, and may manifest in the form of beliefs falling apart, desires not manifesting or, if desires do manifest, the achievement of the manifestation not bringing happiness.
In the most basic terms what you thought you knew, what you desired and what you did no longer have any meaning and that in some way nothing matters any more and you experience some form of pain and suffering.
Hence intellectual knowledge can be called simulacra as it does not reflect the more profound KNOWING of the reality of life but more so an imaginary perception of a likeness of the TRUTH of life.
To obtain the TRUTH and a more profound KNOWING of life, do not look to the outside world, which can include your thoughts and emotions, but LOOK in another direction as suggested by Carl Jung’s quote below.
“Your vision will become clear only when you can look into your own heart. Who looks outside, dreams; who looks inside, awakens.”