1) There is the knowledge of reason (διάνοια), which logically “draw[s] conclusions or formulate[s] concepts deriving from data provided either by revelation or spiritual knowledge or by sense observation.” This kind of knowledge is the most recognized as knowledge by much of the contemporary world, especially with the rise of materialistic empiricism that considers sense observation to be the only reliable source of knowable data. Though this is a false premise, we must not allow this to motivate us to discount rational knowledge. “Even though what [rational knowledge] says about God may not be entirely adequate, it says nothing which is opposed to God.” The fathers do not discount rational knowledge, but they insist that there is also another, deeper, truer kind of knowledge.
2) There is also spiritual knowledge, which is
the knowledge of the intellect (νοῦς) as distinct from that of the reason (διάνοια). As such, it is knowledge inspired by God, and so linked with contemplation (θεωρία) and immediate spiritual perception.Spiritual knowledge directly apprehends or perceives “the inner essences or principles of created beings” and ultimately even “divine truth itself.” Only by direct experience of God can one come to know God spiritually.
|+ Fr. John Meyendorff|
apophatic theology is much more than a simple dialectical device to ascertain the transcendence of God in terms of human logic. It also describes a state, beyond the conceptual process, where God reveals himself positively to the “spiritual senses,” without losing anything of His transcendence.Because of the inadequacy of words to describe the experience of the presence of God, negated terms more closely approximate the truth of God, but even these terms must be negated, for God transcends even their contradiction. Negative theology must not convey an absence of God nor agnosticism toward God, but rather his transcendentally knowable transcendent presence. “The mystical presence of God experienced through [apophatic knowledge] transcends the possibility of being defined in words.”
 G.E.H. Palmer, Philip Sherrard, and Kallistos Ware. “Glossary.” The Philokalia. Vol. 2. London: Faber and Faber, 1981. 386.
 Staniloae, 95.
 This is how the editors of The Philokalia translate γνῶσις, which is knowledge itself.
 Palmer et al., 387.
 Ibid., 386.
 Gregory Palamas. Gregory Palamas: The Triads. Mahwah: Paulist Press, 1983. 32.
 John Meyendorff. “Introduction.” Gregory Palamas: The Triads. Mahwah: Paulist Press, 1983. 15.
 Staniloae, 95.