Pannenberg suggests that we gloss pneuma and ruach in the Bible along the lines of “force” or “power” and not in the Stoic terms of “mind” (Systematic Theology, Vol 1, pp. 372ff). Origen defined incorporeality as God’s undivided simplicity (de Principiis, I.1.3-4, 6). This meant that Origen would interpret all statements about God anthropomorphically but literally those that stressed his rationality.
Panneberg takes the NT use of “spirit” and superimposes it upon the OT usage. Ruach does not mean “reason or consciousness.” Rational thinking and judgment, rather, are located in the heart.
Sometimes it means simply a natural, invisible, yet mysterious force. Or it could be divine. It is the origin of all of life (Ps. 104:29; Job 34:14-15). It is the breath that gives us life (Gen. 2:7). With our last breath it returns to God (Eccl. 12:7).
The ruach of Yahweh is a creative, life-force. Only seldom does it correspond to what we call “spirit,” or thinking-consciousness.
Plotinus highlighted a problem in Platonic views of God: If God is nous then he can’t be utterly One or simple. The nous is subordinated to the One. The nous is always related to the “other” that it knows and so cannot be the final unity (Enn. 6.9.2; 3.8.9; 5.1.4).