What is "Negative Theology" (NT)?
The concept of "Negative Theology" seems to be rarely discussed in the current Orthodox world but it is an essential component of Torah theology that was well known to the medieval rabbis.
Negative Theology is a method of describing Hashem's essence (as opposed to His relationship with the world) using language employing only negative attributes such as "Hashem does not have a body", "Hashem is not a man", "Hashem does not occupy space", etc.
These types of descriptions are necessary because Hashem's "essence" does not resemble anything in the Universe He created so we have no positive language to describe Him.
Our understanding is limited to Hashem's relationship with the world, not to Hashem's essence. For example "aveinu malkeinu" does not mean Hashem is a father as we know it, it means Hashem relates to us as a father does to children. For those who might believe that "Kabbalah" has replaced the medieval concepts of Negative Theology, please see Section 46 of the Ramchal's Daas Tevunos where he strongly emphasizes the basic concepts of Negative Theology. The Ramchal was certainly a rabbi who was knowledgeable in "Kabbalah".
The hashkafacircle site provides some of the best available shiurim on the subject of Negative Theology. www.hashkafacircle.com/category/moreh-nevuchim/page/2/