Use 'hypothesize' when proposing an idea with little evidence, not for strong proven facts. After finding a strange fossil, she hypothesized it was a new species.
Pro Tip 2/3
Beginning Stage
'Hypothesize' is often the starting point in scientific research or discussion. Before testing, they hypothesized that the chemical would be non-reactive.
Pro Tip 3/3
Exploratory Nature
Use 'hypothesize' to express an open-minded stance towards possible explanations. He hypothesized about the cause of the phenomenon, not committing to one theory.