Words like perhaps, maybe, possibly and probably should be banned from your writing.
These verbal qualifiers make your writing passive and impotent. They weaken your arguments. They make your thoughts sound inconclusive and your mind seem indecisive.
Insecure writers use qualifiers when they fear that their views, stated clearly and directly, might antagonize readers. The ironic truth, however, is you antagonize your readers more when you don't just come out and say what you're trying to say. Don't run and hide.
Remember: Make definite assertions. Respect your readers. Don't waste their time mincing around with namby-pamby words.
Readers won't consider your views if they smell weakness in your prose.