The relation between matter and form, or between _content and form_, as it is generally called, is one of the most disputed questions in Aesthetic. Does the aesthetic fact consist of content alone, or of form alone, or of both together? This question has taken on various meanings, which we shall mention, each in its place. But when these words are taken as signifying what we have above defined, and matter is understood as emotivity not aesthetically elaborated, that is to say, impressions, and form elaboration, intellectual activity and expression, then our meaning cannot be doubtful. We must, therefore, reject the thesis that makes the aesthetic fact to consist of the content alone (that is, of the simple impressions), in like manner with that other thesis, which makes it to consist of a junction between form and content, that is, of impressions plus expressions. In the aesthetic fact, the aesthetic activity is not added to the fact of the impressions, but these latter are formed and elaborated by it. The impressions reappear as it were in expression, like water put into a filter, which reappears the same and yet different on the other side. The aesthetic fact, therefore, is form, and nothing but form. From this it results, not that the content is something superfluous (it is, on the contrary, the necessary point of departure for the expressive fact); but that _there is no passage_ between the quality of the content and that of the form. It has sometimes been thought that the content, in order to be aesthetic, that is to say, transformable into form, should possess some determinate or determinable quality. But were that so, then form and content, expression and impression, would be the same thing. It is true that the content is that which is convertible into form, but it has no determinable qualities until this transformation takes place. We know nothing of its nature. It does not become aesthetic content at once, but only when it has been effectively transformed. Aesthetic content has also been defined as what is _interesting_. That is not an untrue statement; it is merely void of meaning. What, then, is interesting? Expressive activity? Certainly the expressive activity would not have raised the content to the dignity of form, had it not been interested. The fact of its having been interested is precisely the fact of its raising the content to the dignity of form. But the word "interesting" has also been employed in another not illegitimate sense, which we shall explain further on. [Sidenote] _Critique of the imitation of nature and of the artistic illusion._