Apophatic theology, also known as negative theology, is a form of theological thinking and religious practice which attempts to approach God, the Divine, by negation, to speak only in terms of what may not be said about God. It forms a pair together with cataphatic theology (also known as affirmative theology), which approaches God or the Divine by affirmations or positive statements about what God is.

The apophatic tradition is often, though not always, allied with the approach of mysticism, which aims at the vision of God, the perception of the divine reality beyond the realm of ordinary perception.

"Apophatic", Ancient Greek: ἀπόφασις (noun); from ἀπόφημι apophēmi, meaning 'to deny'. From Online Etymology Dictionary:

apophatic (adj.) "involving a mention of something one feigns to deny; involving knowledge obtained by negation", 1850, from Latinized form of Greek apophatikos, from apophasis "denial, negation", from apophanai "to speak off," from apo "off, away from" (see apo-) + phanai "to speak," related to pheme "voice," from PIE root *bha- (2) "to speak, tell, say."

Via negativa or via negationis (Latin), 'negative way' or 'by way of denial'. The negative way forms a pair together with the kataphatic or positive way. According to Deirdre Carabine,

Pseudo Dionysius describes the kataphatic or affirmative way to the divine as the "way of speech": that we can come to some understanding of the Transcendent by attributing all the perfections of the created order to God as its source. In this sense, we can say "God is Love", "God is Beauty", "God is Good".
The apophatic or negative way stresses God's absolute transcendence and unknowability in such a way that we cannot say anything about the divine essence because God is so totally beyond being. The dual concept of the immanence and transcendence of God can help us to understand the simultaneous truth of both "ways" to God: at the same time as God is immanent, God is also transcendent. At the same time as God is knowable, God is also unknowable. God cannot be thought of as one or the other only.

According to Fagenblat, "negative theology is as old as philosophy itself:" elements of it can be found in Plato's unwritten doctrines, while it is also present in Neo-Platonic, Gnostic and early Christian writers. A tendency to apophatic thought can also be found in Philo of Alexandria.

According to Carabine, "apophasis proper" in Greek thought starts with Neo-Platonism, with its speculations about the nature of the One, culminating in the works of Proclus. Carabine writes that there are two major points in the development of apophatic theology, namely the fusion of the Jewish tradition with Platonic philosophy in the writings of Philo, and the works of Pseudo-Dionysius the Areopagite, who infused Christian thought with Neo-Platonic ideas.