Logic can only get us to the (unadulterated) uncaused cause. We can't know by the lights of logic whether this is Jehovah, Brahman, a Pythagorean monad, the One, or some mystery we will never know what.
Sure we can, Pon. Who is the God Who consistently taught Israel and in time the whole world that that there was One Supreme Creator? It was only Jehovah, the God Who revealed Himself to Abraham and Moses Who did that. I don't think you will deny that for more than at least a 1000 years before some good Greek philosophers, at length and with difficulty, finally apprehended this truth and discovered philosophically the First Cause, historically speaking, the Lord God Jehovah had proclaimed it to His Prophets to be announced in His Name.
Interestingly, there are some monotheistic traditions even in Hinduism, which is probably the only main polytheistic religion of today. Of course, it was not consistently taught that there is One Supreme God, and thus by some estimates you have like 33 crore claimed gods today, so the notion of one God and Father of all is lost. Much later reformers like Raja Ram Mohan Roy in India tried to bring back the idea of the Supreme Being. "Brahmo Samaj believe in the existence of One Supreme God — "a God, endowed with a distinct personality & moral attributes equal to His nature, and intelligence befitting the Author and Preserver of the Universe," and worship Him alone." Wiki
Thus, God was not operative to prevent error in Hinduism, as He was in Israel, otherwise the doctrine of One God would have been preserved.
In brief, we know Who the Uncaused Cause is historically because only One God consistently taught the world that there is only One Creator of heaven and earth, and all things within them.
Similarly, we can know God is Good through conscience and natural law.
Natural Conscience is God's first witness that the God Who gave us that conscience is unchangeably Good - and is always inspiring us to eschew what is evil and choose what is good. Hence we believe as St. Paul says, "the work of the law written in their hearts, their conscience bearing witness to them" (Rom 2:15).
The argument that some rejected what their conscience told them - St. Augustine and St. Chrysostom mention this was part of the reason that the eternal Lawgiver decided that the Law written on human hearts was now to be written on tablets of stone and left as an everlasting testimony to man - only shows man is free to reject even what he knows, as he can reject even the Scriptural witness after knowing it, not that he was unable to come to the knowledge (at least in a very basic and elementary way) of good and evil.
To put it as a syllogism,
1. All of us know some acts (killing innocents, rape and sexual abuse, torturing children etc) are objectively wrong and we are bound to avoid them.
2. Therefore, there is a law naturally discernible by our conscience that prescribes what we should avoid.
3. This law cannot be caused by any creature because it is unchanging and eternal
4. It can only come from our eternal Creator, Who consequently is known to be the source of the natural moral law, and so Goodness itself.
If we can know that some acts are always evil, we know there is a law that guides our actions toward seeking Good and avoiding evil. But this could not have arisen through blind forces, and thus conscience leads to God. The 4th way of St. Thomas proceeds along similar lines.
Your thoughts, Pon?
Eta: on the other thing, I agree with Gardener that Banez was wrong. St. Alphonsus rejects "negative reprobation". Cardinal Journet shows the Thomistic Tradition.