n Platonic
terminology the illumination of the mind by the ideas. Thus, finally,
all human activity is referred back to God.

This guiding principle determines Philo's attitude to knowledge,
involving, as it does, that we only know by Divine inspiration, or, as
he says, by the immanence of the Logoi.[261] The possibility of
knowledge was one of the burning questions of the age, and it was the
failure of the old dogmatic schools to answer it which led to a great
religious movement in Greek philosophy. How can man attain to true
knowledge, it was asked, about the universe, seeing that perceptions
vary with each individual, and of conceptions we have no certain
standard? The old Hebrew attitude to this question is expressed by the
verse of the Psalmist: "The heavens are the heavens of the Lord, but
the earth hath He given to the sons of men" (Psalm cxv), which implies
that man must not try to penetrate the secrets of the universe. Philo
is sufficiently a philosopher to desire knowledge about things Divine
and human, but at the same time he has a complete distrust in the
powers of human sense and human reason. About the physical universe he
is frankly a skeptic,[262] but his religious faith leads him to hold
that God vouchsafes to man some knowledge of Himself and of the proper
way of life, _i.e._, ethics. "Man knows all things in God."[363] Plato
similarly had despaired of knowledge of the physical world, and had
turned to the heavenly ideas as the true object of thought. Moreover,
in his early period, while his theory was still poetical and mystical,
he had conceived that knowledge was made possible in the subject, by
the entrance of "forms," or emanations, from the ideas. This theory
Philo adapts to his Jewish outlook. Like Plato, he turns away from the
physical to the ideal world,[264] and he regards the ideas of wisdom,
virtue, bravery, etc., which are theologically powers of God, as
continually sending forth Logoi, forms or forces (the angels of
popular belief), to inform and enlighten our minds. Throughout, God is
the cause of all knowledge as well as of being, for these effluences
are but an expression of God's activity. In Philo's theory, object and
subject are really one. What can be known are the modes or attributes
of God, which philosophically are "Ideas"; what knows is the emanation
of the Idea, which God sends into the human soul that is prepared to
receive it by pious contemplation. "Through the heavenly Wis