(Proverbs 8:5 KJV) O ye simple, understand wisdom: and, ye fools, be ye of an understanding heart.
What is the difference between being “simple” (naive NASB) (6612a) and being “fools” (3684)? Is there any real difference? While you will find many people that both will describe there is a difference. It is the difference between the ignorant and the stupid.
The first group are not seeing what they are capable of seeing. Sometimes it is a matter of maturity. Some math concepts cannot be understood by a child who still thinks in concrete terms. With age, enlightenment will come. Sometimes it is a refusal to admit what is obvious. This is much more common in the masses. We often don’t want to deal with reality.
The second group has limited ability. Some people who breeze through algebra seem to have a mental block when it comes to geometry. I am a messy. I don’t see clutter that drives others crazy.
So? It may be hard for you to know the difference in others but you should be able to see it in yourself, if you are honest. Understand that this verse declares there is hope for both groups.