Ruling out various 'ultimate origin' candidates

Let S be a metaphysically possible concrete state of affairs and consider the following metaphysical principle. If a near alternative for S is conceivable, then S is not self-explaining. This principle is plausibly true. Take for example an iron sphere. We can conceive of quite a few near alternatives for this sphere. One could think of various slightly bigger or slightly smaller iron spheres. Or one could think of all kinds of iron ellipsoids that almost overlap with the sphere in question. And indeed, it is reasonable to hold that an iron sphere is not an self-explaining entity. If we observe an iron sphere we can properly ask for an external cause since there is nothing in the sphere itself that could explain its existence. In general there are many other examples that confirm the above principle. Therefore, in the absence of counter examples, we are epistemically justified in accepting it. Now, consider a cosmological theory according to which the universe originated from a single concrete dimensionless point. Suppose that this theory is true. Could we then reasonably believe that the concrete dimensionless point is also the ultimate origin of the world? I show that this is not the case if we accept the above principle. First, we can conceive of near alternatives for the concrete point. Conceive for example of a vacuum sphere of infinitesimally small diameter. Or conceive of a vacuum ellipsoid of infinitesimally small volume. These spheres and ellipsoids are indeed conceivable near alternatives for the point in question. But then it follows, according to the principle, that the point is not self-explaining and thus not a regress-of-explanation-ender. Second, reasonably, we may hold that the ultimate origin of the world constitutes an ultimate explanation and thus is in fact a regress-of-explanation-ender, so that it follows that the point can indeed not be considered as being the ultimate origin of the world. The ultimate origin of the world must be of another character. In this respect it is important to note that the principle cannot be used to infer that God as conceived by traditional theism is not self-explaining. After all, there is no conceivable near alternative for an omnipotent, omniscient and omnibenevolent immaterial being. The principle is thus consistent with the thesis that the ultimate origin of the world is God [1]. Therefore it cannot rule out this thesis. So, we conclude that the principle can only be used to rule out various (and perhaps even all) proposed alternatives for God as the ultimate origin of the world, such as the aforementioned concrete dimensionless point. This, I would say, is a quite interesting observation.

[1] According to this thesis the ultimate origin is actually a free will act of God. This is not problematic though, since free will acts are self-explaining. In the case of the proposed concrete point the scenario is presumably that the point tunnels into our expanding universe in accordance with some natural law. But that is problematic if we, as normally is done, take it that lawfull physical descriptions are not self-explaining. For in that case the concrete point on which the law supervenes is not self-explaining either, and thus not the ultimate origin of the world.