I’m convinced that Satan is an eminently rational being. He understands human nature better than we do. Think about this. Even when tempting Christ, he zeroed in on the potential weaknesses of His human nature: hunger after forty days of fasting; the agoraphobic insecurity of suddenly standing on the very pinnacle of the temple; an option to sidestep the way of the cross which Christ was destined to endure in order to redeem a fallen world. This was exquisite, methodical, purposeful temptation aimed at the human nature of Christ.
He is not insanely or irrationally continuing to fight against God even though he knows from Scripture that he is a defeated foe (Luke 10:18). He knows he can never separate us from the love of Christ (Romans 8:35). He realizes if we resist him, he will eventually flee (James 4:7). He recognizes that we can do all things through Christ who strengthens us (Philippians 4:13). Despite all this, he prowls around like a lion, seeking someone to devour (1 Peter 5:8). This is not insanity; it is intentionality. There is a method to what seems to be madness. His continued efforts in temptation have a purpose.
I think the answer is that Satan is a behaviorist; a stone-cold Skinnerian of the nth degree. Through temptation, he intends to elicit learned helplessness in the life of believers.
Learned helplessness is a principle of behavioral psychology. When an organism (human or animal) repeatedly endures a painful or unpleasant stimuli from which they cannot escape, they eventually become unable or unwilling to avoid further pain or unpleasantness—EVEN IF they could escape from it.
So what would this look like? Imagine an experiment where a dog is placed within a two-sided wire cage with a middle wall. The middle wall can be raised to completely block access to one side; or have the top half of the wall lowered completely. Each side of the cage is independently wired to give a very uncomfortable, but not deadly shock to the dog. Then the experimenter begins to shock the side of the cage in which the dog is.
The dog quickly learns to jump to the other side of the cage to avoid the shock. Then the middle wall is raised and locked. And the side containing the dog is shocked; and shocked; and shocked repeatedly. Ultimately the dog will just lie there and wine and wriggle a bit when the shock occurs. Then the wall is lowered, but the dog continues to lie on the side receiving the shock. This is learned helplessness.
So that is what temptation is all about. It is aimed to convince those who believe in Christ—those who can claim the truth of all the above-mentioned Scripture passages and more—that all they can do is lie there like a dog in the midst of their struggles against sin. Satan teaches the reality of Romans 7:15-24a, but leaves off the hope of 24b and 25: “Who will deliver me from this body of death? Thanks be to God through Jesus Christ our Lord! So then, I myself serve the law of God with my mind, but with my flesh I serve the law of sin.”
If our response to the inescapable pain and suffering of sin is learned helplessness instead of perseverance, then our faith and service to God is overcome. This is the purpose and goal of temptation. We are robbed of faith; and God is robbed of what is pleasing to Him—our turning to Christ for deliverance. If all we can do is stand and face towards the direction we know God wants us to travel, then eventually we will endure, because we can do all things through him who strengthens us.