How tall does your clock say you are? This sounds like a silly question. And it is! How can a clock measure your height? A clock was not designed for telling height, but telling time. Therefore, it does not work for telling height. To understand what a clock does, one must understand why the clock was built.
In much the same way, the only way to trust the human mind is to first acknowledge the designer. As a clock was designed to measure time, so also were our minds designed for intelligent, and more importantly wise thoughts. Therefore, the fear of the Lord is the beginning of wisdom. Without God, we cannot even be sure we are reasonable beings.
But does a clock always tell the right time? The answer to that is, of course, no. A broken clock is right only twice a day (if that). So, we obviously need more than just to know what the clock was designed to tell the time. We must know A. that it is up to the task, and B. how to get it there in the first place.
In much the same way, the fact that we are designed for wisdom does not assure us we will obtain it. Thus, we need to heed our Creator's instructions. He will tell us how to "wind ourselves up", so to speak. By following His instructions, we will obtain wisdom. Failure to heed the word of God is as foolish as trying to measure your height with a clock.