Technically, no. You need two or more people to play a proper game of Truth or Dare. That being said, you can use a Truth or Dare generator by yourself to practice for a game and decide what truths and what dares you'd be willing to accept in a real game. It's also a good way to prepare both truth and dare questions for others so you don't have to spend a lot of time trying to come up with good questions during the game.