Man might, through reason, posit the existence of a creator god.
I respond that it should be said that this is not the question whether God can be seen immediately in His essence, for this belongs to another discourse. The question is whether (God) can be known in any way at all. And so we say that God is knowable; not however that He is so knowable that His essence can be comprehended. [Aquinas, Commentary on the First Book of the Sentences of Peter Lombard, Distinction III, Question 1, Article 1, " Whether God can be known by the created intellect"]
However, the True God is utterly unique. He is not one type of a larger category, that is a fallacy of relativism and modernism. God as Trinity cannot be reasoned to from the ground up, that could only come to us by revelation, a revelation that God initiated.
I respond that it should be said that through natural reason, one is not able to come to a knowledge of the Persons of the Trinity; and so philosophers knew nothing about this except perhaps through revelation or through hearing (about it) from others. The reason for this is that natural reason cannot know God except from creatures. Everything, however, which is said about God on the basis of creatures pertains to the Essence and not the Persons (of God). And so from natural reason one does advance only to the attributes of the Divine Essence. [ibid, Question 1, Article 4, " Whether philosophers by natural knowledge knew the Trinity from creatures"]
God as Trinity implies Creation. Since "the only-begotten Son of God" was "born of the Father before all ages", it follows that God always intended to become incarnate as a man. We know from the tradition regarding Lucifer that he fell because he would not bow to man. This was because God knew He would become a man, and that all creatures would bow to Him as Creator and King. The purpose of this was to bring man to Himself. How does He make this come about?
When we speak of God the Father and God the Son, we refer to a relationship that is a greater-than-human relationship. God is more Father to Jesus the Son than I am to my son, or that any man is to his son, and Jesus is more Son to His Father than any man is to his father. It is more perfect and pure. That doesn't imply there is something wrong with the human father-son relationship, it is natural and what it is supposed to be, but the way it is lived in Christ and in the Father is the Perfect model. Similar to when Jesus says, "Be you therefore perfect, as also your heavenly Father is perfect", [Matthew 5:48] and therefore does not lower the bar for us, so the Church never teaches it is okay to sin, because it must uphold the Perfect model.
When Jesus said to Philip, His disciple who asked Him to show them the Father, "... Have I been so long a time with you; and have you not known me? Philip, he that seeth me seeth the Father also. How sayest thou, shew us the Father?" [John 14:9] He is saying that He, Jesus, is the image of God the Father, the human image. The same substance of God the Father is in the Son, in a way that is different from how the genes of a human father are in his son. The latter is a different, less perfect, representation of the Divine parenthood.
Jesus received His human nature through the passing on of the genes of Mary, but His Divine Nature through the Spirit. Here, again, is the contact point of Heaven and earth. Mary conceived when the Holy Spirit "overshadowed" her. [Luke 1:35] In this way, too, does the Eucharist become Jesus. The Holy Spirit overshadows the Catholic priest when he speaks the words of consecration, and the bread and wine become the Body and Blood, Soul and Divinity of Jesus Christ. Jesus is "born" on the altar. He lives and then "dies" within us. And within us He is resurrected. Thus, as He says of His blood, "For this is my blood of the new testament, which shall be shed for many unto remission of sins." [Matthew 26:28] He dies for the many who partake of His body and blood. Jesus was the only man found worthy to stand in the Presence of the Heavenly nature of God the Father in Heaven. Only Jesus can withstand the Presence of the Father, because no one can stand in His Presence in sin. A man who stands before God the Father in His Heavenly Nature will die. God's Will is to reveal Himself to us, but His Presence will drive out sin, because God and sin can have no part in each other. (Which is why Mary is the Immaculate Conception.) His Presence is Mercy, but also Justice and Wrath. Only Jesus can shield us from the Justice and Wrath, because He is the same substance as the Father. And for us to approach the Mercy, Justice and Wrath, we must be of the same flesh as Jesus. "He that eateth my flesh, and drinketh my blood, abideth in me, and I in him." [John 6:57] "I am the vine: you the branches: he that abideth in me, and I in him, the same beareth much fruit: for without me you can do nothing." [John 15:5] In order to approach the Father, we must abide in Jesus, we must become part of the Body of the Son.
The question arises, whether one must be Catholic to go to Heaven. The document of the Second Vatican Council, Decree On Ecumenism, or Unitatis Redintegratio, discusses many of the varied angles to approach this question. There is, however, a reality we must address.
Jesus Christ is Heaven. If you have a problem with Jesus Christ, you have a problem with Heaven.
The Holy Eucharist is Jesus Christ. If you have a problem with the Holy Eucharist, you have a problem with Jesus Christ.
If the Real Presence of Jesus Christ in the Holy Eucharist attracts you, you may be a Catholic at heart. To find out, visit a nearby Catholic church with an Adoration Chapel. Google it. Go visit during the times it is open. You can walk right in, there are no ID checks. Be quiet upon entering. Sit in the Presence of our Lord, and ask God in your heart if that is Him in the monstrance. Let Him speak to you. You have nothing to lose and Everything to gain.