The simple, the scorner, and the fool, are three terms that describe three categories of people that are progressively more culpable with regard to sin and evil, and their chosen beliefs and way of life.
The simple, describes those that are indifferent through thoughtlessness and indifference, and thereby open themselves up to evil.
The scorner, are those who mock, those who express the voice of derision. Scorners hold all things in derision, both human and divine. They hold contempt for God and openly ridicule everything and everyone.
Fools, describe the hardened. There are those who walk after the sight of their own eyes, or their own imagination. They are driven by the lust of their heart. They are not ignorant of knowledge, but they hate knowledge and truth because of the restraint that it places on them in the pursuit of their sins. They are typically the incorrigible of society, with regard to their attitude.
And the question is, how long? That is to say, how long will you pursue your chosen pattern of life, which is a total disregard for truth, with respect to pretense, or outright outward antagonism.
The simple includes those who talk the talk, but in fact do nothing.
The scorner includes those who have given up on God or truth, because they wrongfully believe that God has failed, when in fact it is they who have failed, through their stubborn opposition toward their spiritual life.
The fools, are the hard-core. They substitute other religions, they invent other philosophies, they have turned their back on reality, and live in their fantasy world which they have made up themselves.
The world is full of these three categories of people.
If you find yourself identifying with any of these three categories, then you need to take a hard look in the mirror at yourself, put your attitude in check, and get back to a day by day study of the word of God.
Knowledge and understanding and wisdom do not come in a day. They only come through a day by day consistent study of the word of God, throughout the course of your entire life.