This Not That

I am this and I am not that
A connective statement to
Identify what it is, the identity

It is this and not that
No way around such
A distinction in description

Confirm that the denial
Engulfs only the expected
Area under the curve

Mathematically, logic
Contains all it extends
Fortitude is irrelevant

Emotionally, language
Articulates this definition
And not that

Yet the human brain
As far as mine can tell
Is both this and that