Convince a Heathen Theologian with 25 years of Experience

Here, I would like to conjure an excercise, as I am well schooled in history and theology of Judeo-Christianity as a side-kick to my Graeco-Roman theological studies and other comparative systems of thought, religion, and philosophy. How would you convince a Heathen to your religion, if: His faith is completely reasonable, not faith-based, namely: claiming hypothesis, building arguments upon arguments of pillar-like soundness that are rock-solid as Parthenon, that reach a conclusion that Polytheism is a natural outcome of the intelligent, and the Monadic "One" is an abstract formula of Pythagorean progressions and theology of arithmetic and geometry. It is therefore a reason-based theology that moves Gods closer, and the remote "En To Pan" is unreachable by the human intellect, reason, anyone claiming to impersonate "objective truth" is a charlatan-guru and realizations of Divinities are approached by establishing ratio and intervals of understanding that correspond with Plotinian "notions" of the metaphysical worlds. Moreover, the aformentioned claims that all religions are man-made, but that does not refute the existence of spiritual worlds, they may be approximated in the eye of the beholder - to a limited extent; there was no reveleation as such, the Gods may or may not reveal themselves, metaphysics and the transcendent realms can do without human belief-systems, a mortal is merely "measuring Heavens and metaphysical realities" with himself, herself, but "heavens and stars are not brought for the sake of a mortal animal" (Iamblichus of Chalcis). His theology relies solely on antique studies, vast literature that is oft ignored by Christians, apart from living experience bestowed by the Providential Gods, starting from Parmenidian doxology, throughout careful understanding of Egypto-Hellenic theologies, into multiple mystery and initiatory cults, psychopompic, psychagogic and otherwise transformative both aretorolically, up to Plotinian Enneads and into Mithraism. He may and understand the cults and their purpose well, which was an effective deification, heroization and epitomization of the soul. Moreover, he is a practicioner of the methods and schools and receives "Theion Ergon", or work of the Divinities upon him, subverting any form of reliance on the Essene Gnostic Jesus and his ecclesiastikoi (the Church). His angelology and bestiaries of spirits are related strictly to Republican and Imperial cults of the Graeco-Romans, avoiding the ideas contained in Dionysos Aeropagite of later "hierarchizations" that was strictly Judeo-Christian. His aretology is based on twenty private and public virtues of Rome and paideic standards of the Hellenes. He doesn't believe in sin or baptism, as an "inventio" of Judaism in face of the dream to be liberated from the Romans, therefore his hamartiology is based not on a "fatal flaw" of birth into nature, but gigantomachia, the battle and overcoming of nature and responsible life, the only transgression is that not to take sculpting in the nature, ethos as a rewarding, heroic enterprise that results in deification posthumously. On top of that, he may be a blatant, openly effective Heathen theurgist and practicing necromancer, an excorcist etc. avoiding all the Judeo-Christian methods of act, belief, and submission. He believes morality is relative, humaneness is difficult to define, and it is by the virtue of his daimon that he becomes noble, bearing, strong and righteous, moreover that human nature - following Plato - is neither good nor evil - every beastiality and idyll may be found amongst nature and the problem of "evil" is that of conflicting natures, war of the elements and inclinations, to be solved first and foremost within by a noble, strong conduct, overcoming suffering not being conquered by it. Is there any argument to convert such a person, or merely "believe because so" is the answer provided to a reasoned, educated Heathen that does not accept the Abrahamic god, nor an Essene gnostic "Jesus" as a figure of any relevance, apart from the creed that professes suhc a belief?