Bro. James encourages us to use God's tools to evaluate our lives instead of our own minds. King Saul and King David each experienced failures when they used their own minds to justify their actions. It is dangerous to use "introspection", defined as using our mind to evaluate our actions, rather than using God's Word to examine ourselves. 

Scriptures referenced: II Peter 1:20, Psalms 19:12, Psalms 90:8, I Cor. 11:26 - 29, Jeremiah 17:5 - 10, I John 3:20 - 22