As he finds himself in the midst of a senseless situation, the prodigal son, finally comes to his senses. The Greek phrase is literally, "when he came to himself." It would be a mistake to understand this as the young man finally exercising some "common sense;" for living the kind of life God desires involves much more than common sense, especially since there is much so-called "common sense" in the world that is simply nonsense.
Jesus' phrase "when he came to himself" is quite interesting. It is a semitic way of referring to repentance, and all that entails-- feeling sorry for one's sins and turning from them-- but it seems that there is something more. How is it that a change in mind and deed toward home is coming to oneself?
The son had left home with his inheritance ready to find himself, ready to forge his own destiny. Instead of finding who he was, all he found was emptiness. He left his father to find himself, and found that whoever he was, it was not something he had to discover somewhere out there in a strange place. What the wayward son had come to realize as he fed swine, was that when he left home to find himself, in actuality he lost himself; even worse, he had rejected his identity, who he was. That is why when he finally "came to himself" he knew he had to return home.
In his Confessions, St. Augustine prays, "Our hearts are restless until they find rest in you." Our identity is not something we need to seek. God has "hard-wired" human beings to be in relationship with him. In our very essence, we are made to be in fellowship with God. C.S. Lewis states that all our attempts at finding fulfillment outside of that divine relationship in sex, drugs and alcohol, fame and fortune, are nothing other than poor attempts at seeking God. In his Weight of Glory, he writes, "If we consider the unblushing promises of reward and the staggering nature of the rewards promised in the Gospels, it would seem that our Lord finds our desires, not too strong, but too weak. We are half-hearted creatures, fooling around with drink and sex and ambition when infinite joy is offered us, like an ignorant child who wants to go on making mud pies in a slum because he cannot imagine what is meant by the offer of a holiday at sea. We are far too easily pleased."
For too long the younger son had tried to find contentment in the mud of sin and found himself literally stuck in it. Thus, when he came to himself, he understood that his identity, who he was, was not to be claimed, but had claimed him long ago. He could only be himself back at home in loving relationship with his father.
And so it is with us. We do not claim our identity; God has claimed us and has sealed that claim in the work of Jesus Christ. We are not our own, and any attempt to find ourselves apart from that divine relationship will lead us to nothing other than a nonsensical existence. It does not matter what we may achieve and who may applaud our accomplishments. The only way to live life with sense is to live life in keeping with the will of God.
When this happens foolishness will give way to wisdom.