Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The Latin phrase argumentum a fortiori denotes "argument 'from [the] stronger [reason]'."In the natural sciences and in social and other human sciences where statistics plays a large role, the phrase is used to mean "even more likely" or "with even more certainty." For example, if a scientist observes certain phenomena to be present in conjunction a given percentage of the time, they may make the argument that each of the individual phenomena will a fortiori be present a greater percentage of the time (because the latter figures, but not the former, will include the occasions on which a given phenomenon is present but one or more of the others are not).