There are various assertions contained in this extract which came to be considered as standard maxims, and which occur constantly in the writers of the middle ages. Such are, for instance, the maxim, "Verè scire est per causas scire;" the remark, that compounds are known to us before their parts, and the illustration from the expressions used by children. Of the mode in which this subject was treated by the schoolmen, we may judge by looking at passages of Thomas Aquinas which treat of the subject of the human understanding. In the _Summa Theologiæ_, the eighty-fifth Question is _On the manner and order of understanding_, which subject he considers in eight Articles; and these must, even now, be looked upon as exhibiting many of the most important and interesting points of the subject. They are, _First_, Whether our understanding understands by abstracting ideas (_species_) from appearances; _Second_, Whether intelligible species abstracted from appearances are related to our understanding as that _which_ we understand, or that _by which_ we understand; _Third_, Whether our understanding does naturally understand universals first; _Fourth_, Whether our understanding can understand many things at once; _Fifth_, Whether our understanding understands by compounding and dividing; _Sixth_, Whether the understanding can err; _Seventh_, Whether one person can understand the same thing better than another; _Eighth_, Whether our understanding understands the indivisible sooner than the divisible. And in the discussion of the last point, for example, reference is made to the passage of Aristotle which we have already quoted. "It may seem," he says, "that we understand the indivisible before the divisible; for _the Philosopher_ says that we understand and know by knowing principles and elements; but indivisibles are the principles and elements of divisible things. But to this we may reply, that in our receiving of science, principles and elements are not always first; for sometimes from the sensible effects we go on to the knowledge of intelligible principles and causes." We see that both the objection and the answer are drawn from Aristotle. We find the same close imitation of Aristotle in Albertus Magnus, who, like Aquinas, flourished in the thirteenth century. Albertus, indeed, wrote treatises corresponding to almost all those of the Stagirite, and was called the _Ape of Aristotle_. In the beginning of his _Physics_, he says, "Knowledge does not always begin from that which is first according to the nature of things, but from that of which the knowledge is easiest. For the human intellect, on account of its relation to the senses (_propter reflexionem quam habet ad sensum_), collects science from the senses; and thus it is easier for our knowledge to begin from that which we can apprehend by sense, imagination, and intellect, than from that which we apprehend by intellect alone." We see that he has somewhat systematized what he has borrowed.