22. These considerations draw a dividing line between the intellect and the imagination; a line which all the scholastics drew, which Descartes and Malebranche respected and made still more prominent, but which Locke began to efface, and Condillac entirely obliterated. All the scholastics recognized this line; but they, like many others, used a language which, unless well understood, was of a character to obscure it. They called every idea an image of the object, and explained the act of the understanding as if there were a kind of form in the understanding which expressed the object, just as a picture presented to the eyes offers them the image of the thing pictured. This language arose from the continual comparison which is very naturally made between seeing and understanding. When objects are not present we make use of their pictures, and thus, since objects themselves cannot be present to our understanding, we conceive an interior form which performs the part of a picture. On the other hand, sensible things are the only ones which are strictly susceptible of representation; we never discover within ourselves the form in which the objects are portrayed, except in the case of imaginary representations; and therefore it was rash to call this an idea, and every idea an imaginary representation, in which the whole system of Condillac consists. 23. St. Thomas calls the representations of the imagination _phantasmata_, and says that so long as the soul is united to the body we cannot understand except _per conversionem ad phantasmata_; that is, unless the representation of the imagination, which serves as material for the formation of the idea, and assists in clearing it up, and heightening its colors, precedes and accompanies the intellectual act. Experience teaches that whenever we understand, certain sensible forms relative to the object which occupies us, exist in our imagination. Now, they are the images of the figure and color of the object, if it have any; now, the images of those with which they are compared, or the words which denote them in the language we habitually speak. Thus, even when thinking of God, the very act by which we affirm that he is most pure spirit, offers a kind of representation to the imagination under a sensible form. When we speak of eternity, we see the _Ancient of days_, as we have often seen him represented in our churches; when we speak of the infinite intelligence, we imagine perhaps a sea of light; infinite mercy, we picture to ourselves as a pitying likeness; justice, with angry countenance. To force ourselves to form some conception of the creation, we fancy a spring whence light and life both flow, and thus also we endeavor to render immensity sensible by imagining unlimited extension.