They have never affirm'd any thing, concerning the cause, till the trial was past: whereas, to do it before, is a most venomous thing in the making of Sciences: for whoever has fix'd on his Cause, before he has experimented; can hardly avoid fitting his Experiment, and his Observations, to his Own Cause, which he had before imagin'd; rather than the Cause to the Truth of the Experiment itself. Referring to experiments of the Aristotelian mode, whereby a preconceived truth would be illustrated merely to convince people of the validity of the original thought.