Constants and Variables
This video presents the same text shown beside it, spoken and on screen. It adds nothing the text does not say.
State
Constants (a, b, c…) name specific individuals; variables (x, y, z) range over individuals without naming any.
Show
"s" can name Socrates. "x" names no one — it's a placeholder awaiting quantification.
Watch for
The constant/variable distinction carries the whole system. Blur it and video 268's restrictions will find you.