The Picture of Dorian Gray has been on my list of favorite novels ever since I first read it, though I'll admit I didn't get around to that particular accomplishment until just over a year ago. I was re-reading the last few chapters of the book the other day, and was once more struck by the beauty of the language, the amount of pity Wilde is able to evoke in the reader for the depraved protagonist, and the starkness of the conclusion.
The book's basic conceit, of course, is that Dorian, while still a relatively innocent young man, makes a wish that he will forever retain his youthful beauty while the effects of age and excess are transferred to his portrait (painted by his friend, Basil Hallward). Soon corrupted by the influence of the older Lord Henry, his life becomes a mad pursuit of pleasure which destroys those who enter his sphere. He nevertheless remains young, beautiful, and to all appearances perfectly pure; his wish has been mysteriously granted and the portrait alone bears the outward effects of his sin.
The haunting conclusion to the tale chronicles Dorian's growing despair at the hideousness of the picture after he has spent years in a life of callous debauchery. His explicit choice to designate pleasure as his highest good, to define it as happiness in a sense, has led only to depair, coldness, and cruelty. Wilde never seems to deny pleasure's goodness, but remorselessly displays its insufficiency as the ultimate end of life.
One can hardly avoid thinking of Aristotle at this point: "All men by nature desire happiness", but few are able to discover where it truly lies. The attractiveness of pleasure (or power, or wealth, or honour, as the case may be for each person) dupes many into equating such a lesser good with the highest end of human life - even when those in error are not aware of explicitly making such an equation.
Attractiveness aside, it is intrinsically impossible for a good like pleasure to satisfy human longings for something higher. Thus we see in Dorian also a passion for beauty. He corrupts this throughout most of the novel by treating this passion as merely another desire to be gratified. External beauty, he thinks at first, will be enough for him; his natural beauty and the beauty he attempts to create by surrounding himself with decadence should suffice. Yet it is not enough. Somewhere in the soul, there is a longing for true beauty that runs deeper than his. The picture makes it impossible to deny that his physical appearance is no more than a facade, and the knowledge of the hideous state of his soul torments him.
Though Dorian would not have recognized the fact (perhaps even Wilde did not fully when he wrote it), this yearning for the expunging of his hypocrisy, for genuine beauty, for truth, is in the end - from a Catholic viewpoint - a yearning for God. God is Beauty. He is Truth. Without Him, every other good becomes cold, cruel, void of meaning. Like Hallward, Wilde has painted a picture of a soul - a picture of every soul in a sense - and in its center is the gaping hole of which St. Augustine speaks: the God-shaped hole which makes every human heart "restless until it rests in Him".