The Principia Mathematica is written by Alfred North Whitehead and Bertrand Russell and published in 1910–1913. It is an attempt to derive all mathematical truths from a well-defined set of axioms and inference rules in symbolic logic. One of the main inspirations and motivations for the Principia was Frege's earlier work on logic, which had led to paradoxes discovered by Russell. These were avoided in the Principia by building an elaborate system of types: a set has a higher type than its elements and one can not speak of the "set of all sets" and similar constructs which lead to paradoxes (see Russell's paradox).
(lifted from Wikipedia)
These words may very well have been:
...to me. I was already lost by the first sentence.But this next illusion, this I get.
If you concentrate on the black spot... the grey haze around the spot disappears.
Let us assign spot= joy and grey haze = crap.
Focus on joy and crap has less value.
Conversely,
If spot= sadness and grey haze = joy,
Focus on sadness and joy has less value.
(She said to herself)