Double Negative — ruling 1

You may cast Double Negative with no targets, one target, or two targets.

Double Negative — ruling 2

In order to counter two target spells, both of those spells must be on the stack at the time you cast Double Negative. Two spells can be on the stack at the same time as the result of an ability (such as cascade or replicate), as the result of a copy effect (such as the one from Cloven Casting or Twincast), or because a spell has been cast in response to another spell.

Double Negative — ruling 3

It’s unusual for a player to cast a spell in response to their own spell, and that will be specifically called out when it happens. Under normal circumstances, if a player casts a spell, it is assumed that the player passes priority afterward. If that player casts another spell, it is assumed that each other player has also passed priority, which caused the first spell to resolve and the first player to receive priority again. Unless the first player says otherwise, only one spell will be on the stack at a time in that scenario.

Double Negative : règles, fonctionnement et interactions (MTG)

Double Negative 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

Counter up to two target spells.

How it works : Double Negative

Original English text — Wizards of the Coast / Scryfall

#1May 1, 2009· Wizards of the Coast
You may cast Double Negative with no targets, one target, or two targets.
No other card is named in this ruling.
#2May 1, 2009· Wizards of the Coast
In order to counter two target spells, both of those spells must be on the stack at the time you cast Double Negative. Two spells can be on the stack at the same time as the result of an ability (such as cascade or replicate), as the result of a copy effect (such as the one from Cloven Casting or Twincast), or because a spell has been cast in response to another spell.
No other card is named in this ruling.
#3May 1, 2009· Wizards of the Coast
It’s unusual for a player to cast a spell in response to their own spell, and that will be specifically called out when it happens. Under normal circumstances, if a player casts a spell, it is assumed that the player passes priority afterward. If that player casts another spell, it is assumed that each other player has also passed priority, which caused the first spell to resolve and the first player to receive priority again. Unless the first player says otherwise, only one spell will be on the stack at a time in that scenario.
No other card is named in this ruling.