smallest details, follow from the thoroughly understood and consistently carried out conception of the amply adequate support of a given burden, thus so far are determined _a priori_, it comes out clearly how perverse is the thought, so often repeated, that the stems of trees, or even (which unfortunately even “Vitruvius,” iv. 1, expresses) the human form has been the prototype of the column. For if the form of the column were for architecture a purely accidental one, taken from without, it could never appeal to us so harmoniously and satisfactorily whenever we behold it in its proper symmetry; nor, on the other hand, could every even slight disproportion of it be felt at once by the fine and cultivated sense as disagreeable and disturbing, like a false note in music. This is rather only possible because, according to the given end and means, all the rest is essentially determined _a priori_, as in music, according to the given melody and key, the whole harmony is essentially so determined. And, like music, architecture in general is also not an imitative art, although both are often falsely taken to be so. Æsthetic satisfaction, as was fully explained in the text, always depends upon the apprehension of a (Platonic) Idea. For architecture, considered merely as a fine art, the Ideas of the lowest grades of nature, such as gravity, rigidity, and cohesion, are the peculiar theme; but not, as has hitherto been assumed, merely regular form, proportion, and symmetry, which, as something purely geometrical, properties of space, are not Ideas, and therefore cannot be the theme of a fine art. Thus in architecture also they are of secondary origin, and have a subordinate significance, which I shall bring out immediately. If it were the task of architecture as a fine art simply to exhibit these, then the model would have the same effect as the finished work. But this is distinctly not the case; on the contrary, the works of architecture, in order to act æsthetically, absolutely must have a considerable size; nay, they can never be too large, but may easily be too small. Indeed _ceteris paribus_ the æsthetic effect is in exact proportion to the size of the building, because only great masses make the action of gravitation apparent and impressive in a high degree. But this confirms my view that the tendency and antagonism of those fundamental forces of nature constitute the special æsthetical material of architecture, which, according to its nature, requires large masses in order to become visible, and indeed capable of being felt. The forms in architecture, as was shown above in the case of the column, are primarily determined by the immediate structural end of each part. But so far as this leaves anything undetermined, the law of the most perfect clearness to perception, thus also of the easiest comprehensibility, comes in; for architecture has its existence primarily in our spatial perception, and accordingly appeals to our _a priori_ faculty for this.