Regulating; tending to regulate.Since Kant, a rule showing what we ought to assume, without giving any assurance that the fact to be assumed is true; or a proposition which will lead to the truth if it be true, while if it be false the truth cannot be attained: such, for example, is the rule that we must not despair of answering any question by sufficient investigation.A rule of conduct which, if it be pursued, may lead us to our desired end, while, if it be not pursued, that end cannot be attained in any way.