It is when the word, intellectualism, begins to mean that the human mind is the source of wisdom, understanding, and knowledge that intellectualism becomes idolatry.  It is an extreme and foolish position to make the intellect equal with God or equal with the Bible.  In fact, the human mind isn't even capable of helping God to interpret the Bible.  The human mind cannot understand spiritual things.  Spiritual things, the Bible, must be interpreted by the Holy Ghost.

Since the fall, even saying that the human mind can figure out the Bible is dangerous.  Note these scriptural warnings against human understanding.  God says that He is the source of all wisdom, understanding, and knowledge.  God created the human mind and gave it great abilities, but God is the keeper of all knowledge and He reveals His knowledge to whomsoever he will.  At the same time, the human mind is very weak and is easily fooled.  So-called "intellectuals" deceive themselves daily and become pawns of Satan.