A pixel is what you define it to be. This is a good thing, as long as your definition is a useful definition for the purposes of the discussion in which it is used.
It only becomes a problem if you're using one definition but your audience is using another, and neither side attempts to clarify what definition they're using, leading to disagreements that sound like disagreements of fact, but are only disagreements of definition.
It only becomes a problem if you're using one definition but your audience is using another, and neither side attempts to clarify what definition they're using, leading to disagreements that sound like disagreements of fact, but are only disagreements of definition.
I.e. just like most debates.