Academic Dispute — ruling 1

The creature blocks only if it's able to do so as the declare blockers step begins. If, at that time, the creature is tapped, it's affected by a spell or ability that says it can't block, or no creatures are attacking its controller or a planeswalker controlled by that player, then it doesn't block. If there's a cost associated with having the creature block, the player isn't forced to pay that cost. If that cost isn't paid, the creature won't block.

Academic Dispute — ruling 2

The controller of the creature chooses which attacking creature that creature blocks.

Academic Dispute — ruling 3

You choose whether you want the creature to gain reach until end of turn as Academic Dispute resolves.

Academic Dispute — ruling 4

If a card is brought into the game from outside the game, it will stay in the game until it ends or until its owner leaves the game, whichever comes first.

Academic Dispute — ruling 5

If you bring a card into the game from outside the game in a Constructed tournament (or a Constructed game played under tournament conditions), you may select only a card from your sideboard. In casual Constructed games, the card comes from your collection.

Academic Dispute — ruling 6

If you bring a card into the game from outside the game in a Sealed Deck or Booster Draft event, you may select only a card that is in the card pool that you built your deck from.

Academic Dispute — ruling 7

If instructed to learn, you may do nothing. Discarding a card and putting a Lesson card into your hand are both optional.

Academic Dispute : règles, fonctionnement et interactions (MTG)

Academic Dispute is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Target creature blocks this turn if able. You may have it gain reach until end of turn. Learn. (You may reveal a Lesson card you own from outside the game and put it into your hand, or discard a card to draw a card.)

How it works : Academic Dispute

Original English text — Wizards of the Coast / Scryfall

#1April 16, 2021· Wizards of the Coast
The creature blocks only if it's able to do so as the declare blockers step begins. If, at that time, the creature is tapped, it's affected by a spell or ability that says it can't block, or no creatures are attacking its controller or a planeswalker controlled by that player, then it doesn't block. If there's a cost associated with having the creature block, the player isn't forced to pay that cost. If that cost isn't paid, the creature won't block.
No other card is named in this ruling.
#2April 16, 2021· Wizards of the Coast
The controller of the creature chooses which attacking creature that creature blocks.
No other card is named in this ruling.
#3April 16, 2021· Wizards of the Coast
You choose whether you want the creature to gain reach until end of turn as Academic Dispute resolves.
No other card is named in this ruling.
#4April 16, 2021· Wizards of the Coast
If a card is brought into the game from outside the game, it will stay in the game until it ends or until its owner leaves the game, whichever comes first.
No other card is named in this ruling.
#5April 16, 2021· Wizards of the Coast
If you bring a card into the game from outside the game in a Constructed tournament (or a Constructed game played under tournament conditions), you may select only a card from your sideboard. In casual Constructed games, the card comes from your collection.
No other card is named in this ruling.
#6April 16, 2021· Wizards of the Coast
If you bring a card into the game from outside the game in a Sealed Deck or Booster Draft event, you may select only a card that is in the card pool that you built your deck from.
No other card is named in this ruling.
#7April 16, 2021· Wizards of the Coast
If instructed to learn, you may do nothing. Discarding a card and putting a Lesson card into your hand are both optional.
No other card is named in this ruling.