The proposition that I am in this room does materially imply that I am more than five years old, since both are true; and the assertion that it does is also an instance of a true formal implication, since it is in fact true that all the persons in this room are more than five years old; but nothing appears to me more obvious than that the second of these two propositions can not be deduced from the first that the kind of relation which holds between the premisses and conclusion of a syllogism in Barbara does not hold between them.