hypothesize about (something)
To speculate or wonder about something. Oh, they're just hypothesizing about what happened—there's no way they could know for sure.
hypothesize on (something)
To speculate or wonder about something. A murmur went through the stands as people hypothesized on which dog would be named the winner.
hypothesize about something
to speculate about something; to make guesses about something. Don't waste time hypothesizing about what happened. There is no point in hypothesizing about what happened when we don't know the actual truth.
hypothesize on something
to conjecture on the origin or nature of something. We sat around hypothesizing on the origin of life.