In step one, Samkhya is simply defineing his use of possible. It’s a use I’ve seen before, so even tho its not the main one, it’s legitimate.
Step two seems legitimate, until you take with it the definition of possible in step one.
You see, step two and step three are actually equivalent with this definition and not a logical move per se. Therefore step 3 must be seen as a premise and then it is a question begging one.
There is an equivication.
For me, or other interlocutors to agree with step 2 then the definition of possible must be the same as in, “It is possible that my scratch-off lotto ticket is a winner.”
That is to say possible is that which is actual, potential, or not know to be. In other words, anything that isn’t contradictory with previous knowledge.
Samkhay its a pleasure as always. But I do wonder what is your reason for beliving, if you do belive. For it seems you like to rationalise (in the sense of making plausable sounding reasons instead of revealing your own.)
Your most convinceing argument is likely the one that really got you to your position.
God is the one substance (infinite thing) of which causes all things, Therefore God causes God, not of free will but because it is infinity’s nature to cause itself.
You should read the posts on infinity. All proofs are subjective, anything which can deny logic is not logical.
All theistic proofs rest upon a set of axioms. The goal is to reduce to a minimum the axioms involved in the reasoning by making the maximum of statements as uncontroversial as possible.
The project of providing rational grounds for theism is not so obsolete that nowadays no professional thinker in the field of philosophy of religion would undertake this task. Today there are Swinburne, Craig, Plantinga and perhaps other ones.