The limitations of our sensory and emotional apparatuses (the veil of Maya), deceive us into thinking that anything differs from an underlying unitary truth.
BTW: Schopenhauer's use of the knower and known has been used by both Catholics and Buddhists for over 20 centuries.
The Blessed Trinity is a symbol in traditional western religious philosophy. The number three has for ages been a mystical number in many cultures.
The Blessed Trinity consists of the Father, Son and Holy Spirit The Father is symbolic of or the personification of the Ultimate Divine. For the Father to be known there must be a Knower, God can only be known by God, therefore the second Person of the Blessed Trinity is the Knower, the Son. When there is a knower and known there is a relationship between the two, and this is the Holy Spirit.
If one looks to the ancient holy language of Sanskrit, there are similar features there as in the Blessed Trinity, viz., as sat-chit-ananda, where sat means being, chit means consciousness, and ananda is rapture or bliss, and you have the same relationship.
It appears to be a universal method of grappling with Maya, just like Siddartha did.
nice to see you again fresco. hope all is well.