Point 22: Terms of Certainty

Avoid terms of absolute certainty: clearly, obviously, undoubtedly, certainly, and so on (or worse, "it is clear/obvious/certain that").

These terms sometimes indicate a writer's defensiveness; ironically, the most controversial, unproven arguments in a paper often follow them. If, on the other hand, a statement is genuinely obvious, you can generally omit it because the obvious can remain unspoken.