In debate, one listens to the other side in order to find flaws and to counter its arguments. Dialogue enlarges and possibly changes a participants point of view. Debate affirms a participant's own point of view. Dialogue reveals assumptions for re-evaluation. Debate defends assumptions as truth.
Dialogue causes introspection on ones own position.
Debate causes critique of the other position. Dialogue opens the possibility of reaching a better solution than any of the original solutions. Debate defends one's own positions as the best solution and excludes other solutions. Debate creates a close-minded attitude, a determination to be right. In dialogue, one submits ones best thinking, knowing that other people's reflections will help improve it rather than destroy it.