Hojat Borumandi Nov 15, 2019:

All-or-none law is related mainly to neurology The all-or-none law is the principle that the strength by which a nerve or muscle fibre responds to a stimulus is independent of the strength of the stimulus. If that stimulus exceeds the threshold potential, the nerve or muscle fibre will give a complete response; otherwise, there is no response.
However, black-and-white thinking or all-or-nothing thinking) is the failure in a person's thinking to bring together the dichotomy of both positive and negative qualities of the self and others into a cohesive, realistic whole. It is a common defense mechanism.[1] The individual tends to think in extremes (i.e., an individual's actions and motivations are all good or all bad with no middle ground): https://en.wikipedia.org/wiki/Splitting_(psychology)