Temporal logic puzzle solved as Thursday via flawed reasoning

The answer is Thursday.

Here's the logic:

If tomorrow is yesterday, we have a contradiction that reveals the nature of the statement. Let me work through it:

● If "tomorrow" (the day after today) = "yesterday" (the day before today)
● Then the day after today = the day before today
● This means today is sandwiched between two identical days, which is impossible in normal time

However, we can interpret this as a self-referential paradox about the statement itself. The statement "If tomorrow is yesterday, then today is Friday" is constructed so that:

● The condition "tomorrow is yesterday" is false (it never happens)
● When the antecedent of an if-then statement is false, the implication is vacuously true
● But the puzzle's real trick: the statement is telling us the answer within its structure

The actual answer: If we parse this as a riddle where the premise leads us to determine what day it is, we need to work backward:

● We're told "then today is Friday"
● But the condition is impossible, so we're in the actual world
● The puzzle states tomorrow is not yesterday
● If today is Friday, tomorrow is Saturday and yesterday is Thursday ✓

So if the puzzle is asserting a false premise to guide us, today is Thursday (the day before the Friday mentioned).