@Fil Albuquerque,
I am re posting this because the initial post was already edited several times as there where some logical links I jumped forward in the hurry to present the conclusion.
...I do that often imagining it is not a problem for those you are familiar with the argument nonetheless I recognize it is better to fully explain step by step no matter how annoying it may seam.
The argument against infinite regression being a valid counter to total relativism is flawed for the simple reason that whatever is circumstantial and finite, mankind society and negotiated concepts for instance, in a chain of cause, has a non caused starting point nonetheless. Taking the argument to its ultimate consequence, to its stretching point, by imagining there was only one thing and that such thing was you, the first thing, it still would be a problem to argue for construction of facts once you, the first fact itself
could not build himself from its own strap boots. Something ALWAYS must be a given, n thus something is not bound to be constructed by any agent or anything...
In resume:
The final first cause, cannot cause itself.