Argument for a Beginningless Existence

[Mudhammam]

I don't know if this argument has been made before (it probably has) but I thought I'd present it here and solicit some critiques. The argument is neither atheist nor theist in nature, but attempts to address the issue of first cause vs. infinite regression. 

[i] the Universe Exists. 
[ii] It could not have been the case that there was a state of affairs in which the Universe did not have the potential to exist (or the Universe would not currently exist). 
[iii] This potentiality, whatever its properties, cannot be absolutely nothing.
[iv] Therefore, something has always existed.

I would agree that absolute nothingness has no potentiality to change into something because to "have" any attributes implies a substratum upon which a change of any sort is able to occur, and whatever this substratum is, by definition it certainly cannot be said to be absolute nothingness (since to be anything is to be something). I don't think that your conclusion is necessarily incorrect, and it seems to follow from your three premises, but I might take fault with [ii]. Things get a bit thorny when you begin to speak about a "state of affairs" prior to the Singularity. Either it represents the boundary of all being, in which case there literally is nothing beyond it to ponder, or it represents a discontinuity so radical that any material or spatio-temporal antecedents to the big bang lie outside the scope of any possible investigation.