Is the center of a circle naturally round?

It is obvious that nature does nothing against itself, for if it did, it would not be what it is, but rather something above the course of nature, which is impossible. And because in the center of a pentagon inscribed in a circle there are potential acute angles through continuous lines from the center to the angles of the pentagon, it is therefore obvious that the center of a circle is not naturally round, because if it were, it could not naturally receive the acute angles of the pentagon.

Go to the first principle, and if what you say were simply right, there could be no center in the middle of a circle, as it would not be round.

Why is the diametric line more perfect than any other line?

The reason why the diametric line is more perfect than any other line is that it divides a circle into equal parts.

Go to the second principle, which indicates that because a diametric line is the one that can best participate in its own line, it is more perfect in the center and through the center than on account of anything else, and although it is true that a diametric line is the most perfect because it divides a circle into equal parts, it owes its perfection even more to its participation with many lines at the center.

Why is the center, by nature, more desirable than any other locus?

The reason why the center is more desirable than any other locus is that it is placed in the middle of a circle.

Go to the third principle, and you are right in saying that a point is more perfect in the center than in any other place, and by reason of this perfection, the center is more desirable than any other locus, and because there is more repose in it than anywhere else.

Why can't a figure be without a center?

The reason why a figure cannot be without a center is that in every figure there is a locus in the middle which is its center.

Go to the fourth principle, and you are right in saying that in every figure there is a locus in the middle which is its center. But given that every figure has an appetite that moves it to seek the center, which appetite it would not have without a center, and without this appetite it could not exist, and this is why a figure cannot be without a center.

Where is the center of the Sun?

Since every center is located in the middle, the  center of the Sun's sphere must be located in its middle.

Go to the fifth principle, and you are right with regard to the center of a spherical body, but wrong with regard to a concave body, like the solar sphere as well as the other planetary spheres, which are concave so that the spheres can contain one another. And thus the sphere of Saturn contains the sphere of Jupiter, and the sphere of Jupiter contains the sphere of Mars, the sphere of Mars contains the sphere of the Sun, the sphere of the Sun contains the sphere of Venus, the sphere of Venus contains the sphere of Mercury, and the sphere of Mercury contains the sphere of the Moon; and this is the way it must be, so that they do not lose their shape and leave a void, which they would leave if they were spherical bodies, as mentioned earlier, like two or more eggs touching each other and making a non circular figure.

Does the center have any appetite for motion?

In a very heavy stone, there is a center, and this center desires to be moved toward the nether center, toward which it is moved by its great weight.

Go to the sixth principle, and you are right in saying that a falling stone has an appetite for moving downward, and this is by reason of the general center of water and earth which is the lowest, and which is sought by all other centers belonging to it.

Do the centers of angles have any appetite to be moved?

Since the square and the triangular figure have perfect being due to their angles, the center points of their angles have no desire to be moved.

Go to the seventh principle, and in saying that the centers of the angles in squares and triangles have no appetite to be moved, you are wrong, given the fact that all triangular and square figures are corruptible.

What are the species of the common center?

The common center is a point in a body which is in the middle of a circle, and its species are the angles it potentially holds, inasmuch as it can be the terminus of many lines.

Go to the eighth principle, which indicates that the centers of the angles in squares and triangles are species of the center of the circle, because all other figures arise from the circle; and you are wrong, because potential angles are not actual things.

Which center is the one that does not move?

There can be no center that does not move, since every center was created and every center is moved inasmuch as it is created.

Go to the ninth principle, which indicates that the center which does not move is the center of the earth, and it would be even more perfect if you said that God is the unmovable center which we desire, and there is also the center of fire which is unmovable inasmuch as it is a general appetite though heat, and likewise with other centers, and you are right about creation.

Heating, cooling, growing, seeing and other such secondary attributes are secondary centers. Hence, we ask whether all these modes of action are in the middle between power and object.

If heating, cooling, growing, seeing and other such secondary attributes were not in the middle between power and object, they could not be centers, given that a center, by nature, must be placed in the middle.

Go to the tenth principle, and you are wrong inasmuch as all created secondary acts depend, due to the motion of the major end, more on form than on matter, and by reason of this major end, all secondary created acts move from one end to another.