For as long as humans have lived on earth they have striven to find the meaning of their existence. In Ancient Greece the philosophers studied the universe and its laws. They investigated human nature and human reason, hoping to discover knowledge of the first causes of all things. The philosophers not only engaged in rational debate and logic, but also studied astronomy and physics, mathematics and geometry, music and poetry. A diversity of knowledge was in many cases combined with an ascetic life and prayer, without which it was impossible to obtain a katharsis , a purification of mind, soul and body.

In studying the visible world, philosophers came to the conclusion that there was nothing accidental in the universe, that every detail has its place and fulfils its role by being subject to strict laws: the planets never go out of orbit and satellites never abandon their planets. Everything in the world is so harmonious and meaningful that the ancients called it the 'cosmos', that is, 'beauty', 'order', 'harmony', as opposed to 'chaos' - 'disorder', or 'disharmony'. For them the cosmos is a huge mechanism in which a single unbreakable rhythm is at work, a single regular pulse. But each mechanism must have been created by someone, just as every watch needs to have been constructed and sprung. Thus the philosophers arrived at the idea of a single Author of the Universe. Plato called Him the Creator, Father, God and Demiurge (Maker or Craftsman).

The Greek philosophers also spoke about the Logos (meaning 'word', 'reason', 'idea', or 'law'), which was originally perceived as an eternal and general law upon which the whole world is constructed. However, the Logos is not only an abstract idea: it is also a divine creative force mediating between God and the created world. This was the teaching of Philo of Alexandria and the Neoplatonists.

Plotinus, a representative of the Neoplatonist school, emphasizes the transcendence, infiniteness, limitlessness and incomprehensibility of the Divinity. No definitions can exhaust it, no attributes can be ascribed to it. In being the fulness of Being, the One, as Plotinus calls the highest Principle, God, engenders all other forms of being, of which the first is the Intelligence and the second the Soul. Beyond the confines of the circle of the Soul lies the material world, that is, the universe, into which the Soul breathes life. Thus the world is a kind of reflection of the divine reality and bears within itself the marks of beauty and perfection. The One, the Intelligence and the Soul comprise in total a Divine Triad (Trinity). Through purification ( katharsis ) we can be elevated to the contemplation of God. However, the One still remains incomprehensible and inaccessible. He remains a mystery.

With these examples from Plato and Plotinus we can see that the Greek philosophy comes very close to the truths that are finally to be revealed in Christianity: the one God, the Creator of the world, the divine Logos, the Holy Trinity (Divine Triad), the vision of God, the deification of the human person. This is why early Christian writers called the philosophers 'Christians before Christ'.