Memory Worm

• WOTC Official Reminder Textofficial rules
  Paradox — This ability triggers whenever you cast a spell, then gets more powerful if it was the second, third, or fourth spell you cast this turn.

• WWizards of the Coast2023-10-13
  Official Ruling
  Paradox abilities count any spells cast from zones other than your hand. These are usually spells cast from exile, the graveyard, or the command zone. They also count spells cast from outside the game, such as spells cast with Wish or Garth One-Eye's ability.
• WWizards of the Coast2023-10-13
  Official Ruling
  An instant or sorcery that counts how many spells you've cast from anywhere other than your hand, such as Surge of Brilliance, counts itself if it was cast from a zone other than your hand.
• WWizards of the Coast2023-10-13
  Official Ruling
  If a spell or ability allows you to copy a spell on the stack but doesn't specify that the spell is cast, that spell wasn't cast and won't be counted by paradox abilities. However, if a spell or ability allows you to cast a copy of a spell, that spell will be counted for paradox abilities.
• WWizards of the Coast2023-10-13
  Official Ruling
  A triggered ability that triggers when a spell is cast from anywhere other than your hand, such as that of The Thirteenth Doctor, functions only on the battlefield, so it doesn't trigger when you cast that spell from a zone other than your hand.

Rulings via Scryfall