The Sages' manual for succeeding in Torah study, the 48 ways of acquiring Torah (Avot 6:5, the Baraita of Kinyan Torah), includes a number of striking elements that are very revealing about the Torah itself. After listing a number of study techniques - learning from a teacher, proper listening skills, verbalizing, and deep understanding - the list shifts gears. The next five elements seem to come other areas of experience, from morals, ethics, character, and religious experience.

How do awe, fear, humility, joy and purity impact on Talmud Torah? Further on in the list we also find calmness, good-heartedness, being beloved, loving people, loving G-d, justice, rebuke, straightforwardness, avoiding honor, and judging others favorably. These all seem to be important character traits or aspects of healthy relationships, but out of place in a baraita listing ways of acquiring Torah, not just listing important aspects of a Jewish personality. Apparently, character is an essential element of Torah learning. What is its function?

One direction:
The baraita is pointing out character's impact on the process and effectiveness of learning. For instance:
Humility - A humble person will not be embarrassed to ask questions and will learn (Rashi),
Joy - In a joyous mood much more can be accomplished in one hour than is possible in several hours when depressed (Ruach Chaim),
Beloved - If one is beloved teachers will seek him out as a student (Midrash Shmuel).
Avoiding Honor - One who avoids honor will not hesitate to learn from anyone, even one of lower status, age, or wisdom (Rashi).

The baraita, as in all of the above, cautions us that our intellectual faculties cannot work at full force and our academic activities cannot proceed properly without a fully developed healthy character. It shows us the interconnectedness of the different realms of our life.

A second direction
A number of comments go beyond the practical and naturalistic explanations of the character-Torah connection. They are very instructive about the nature of Torah and Torah learning.

The Maharal on Joy: When joyous one is whole and complete. Through this he is able to accept the Torah, which brings wholeness and completeness to man. Man can only reach his Divine completeness if he is in a state of completeness of the soul.
The Maharal on Goodheartedness: The Torah is called "good" and can only be received by one who is also "good" (= one who has a good heart). How can the Torah which is good exist in one who is not good? We must be fitting for the Torah, says the Maharal. Certain character traits create an appropriate and proper setting and environment for the Torah and others do not.
Rashi on Joy: The Divine Presence only rests on one who is joyous.

This Rashi sheds light on the whole enterprise of Talmud Torah. Learning Torah, says Rashi, is receiving the Divine Presence, the Shechina. Preparing ourselves for the Torah is identical with preparing ourselves for prophecy and ruach hakodesh. This also explains the need for fear and awe when learning. The experience of learning Torah is akin to the original experience of receiving the Torah at Sinai. We must develop a character that fits it.