Apophatic theology

Apophatic theology -- from wiki

is a theology that attempts to describe God by negation, to speak of God only in terms of what may not be said about God.

In brief, the attempt is to gain and express knowledge of God by describing what God is not (apophasis), rather than by describing what God is. The apophatic tradition is often, though not always, allied with the approach of mysticism, which focuses on a spontaneous or cultivated individual experience of the divine reality beyond the realm of ordinary perception, an experience often unmediated by the structures of traditional organized religion or learned thought and behavior.

http://en.wikipedia.org/wiki/Apophatic_theology

from wiki article on Maimonides:

One of the central tenets of Maimonides's philosophy is that it is impossible for the truths arrived at by human intellect to contradict those revealed by God. Maimonides held to a strictly apophatic theology in which only negative statements toward a description of God may be considered correct. Thus, one does not say "God is One", but rather, "God is not multiple".