Much secular thought is godless or anti-God.
Job 21:14
Romans 1:28
2 Corinthians 11:3
Colossians 2:6-8

The wisdom of this world is actually foolishness.
Psalm 14:1
Jeremiah 8:9
Zechariah 7:11-12
Romans 1:21-22
1 Corinthians 1:18-21
1 Corinthians 3:19

False science—secular humanism's god—doesn't have the answers to life's big questions.
Isaiah 44:24-25
Jeremiah 2:27
Romans 1:25
1 Timothy 6:20
2 Timothy 3:7

Faith vs. natural reasoning:
1 Samuel 16:7
Psalm 118:8
Proverbs 3:5-6
Isaiah 11:3
Isaiah 55:8-9
Jeremiah 17:5
1 Corinthians 2:5
1 Corinthians 2:14
2 Corinthians 5:7

Being "smart" or highly educated is not a prerequisite to being used by God or being filled with His wisdom.
Psalm 8:2
Psalm 119:99
Luke 10:21
John 7:15
Acts 4:13
1 Corinthians 1:26-27