When [our] divine enlightenment is small
This occurs, for instance, when a person pictures God as a pedantic judge, concerned above all with obedience to God's commands, incessantly monitoring people's submission. Such an image of God as the supreme overseer is a monstrous primitivization of both God and the person who so imagines the divine. (See also First Journal, Shemonah Kevatsim I, paragraph 75.)
Inasmuch as all people imagine themselves in relation to their idea of God (after all, God created humans in the divine image and likeness), those who picture God as small see themselves as utterly insignificant.
In other words, fear of God without breadth of understanding causes a person to feel worthless.
For a religious person not only is it not forbidden to study everything that exists, it is commanded.
Rav Kook is speaking here of the person who, having knowledge of all human culture, remains true to the Torah, and builds his worldview on its foundation.
If we interpret the words of the Torah too narrowly, we will not be able to build a full-blooded life; we therefore need to apprehend it "in its most absolute breadth."
This refers to such risks as the danger that knowledge of the wide world can lead to rejection of Judaism.
In other words, the person who fears everything will achieve nothing, whereas only the person who understands that truth in is the Torah, but at the same time studies other cultures, languages, and learning, distinguishing and sifting the good from the bad, can rectify the world.