The Buddha taught some people the teachings of duality that help them avoid sin and acquire spiritual merit.
To others he taught non-duality, that some find profoundly frightening.
Even offering three hundred bowls of food three times a day does not match the spiritual merit gained in one moment of love.
All philosophies are mental fabrications.
There has never been a single doctrine by which one could enter the true essence of things.
~ Nagarjuna (150 - 250 CE)