In 2013, the United Nations declared March 20^th the International Day of “Happiness.” That same year Pharrell Williams released his widely popular song “Happy.” A simple search on Amazon lists thousands of books on happiness. I think it is safe to say that our culture is fixated on happiness. But what is happiness? What does happiness consist of? Why is it important that we get the happiness question right? Pharrell Williams seems to leave the happiness question up to us: “Clap along if you know what happiness means to you?” In other words, we define what happiness is for ourselves. But what if we’re wrong? Being wrong about happiness could lead someone to think their life is not worth living. Our view of happiness is connected to our view of the meaning of life because the desire for happiness is built into the very fabric of our being. We cannot help but desire to be happy (Thomas Aquinas, Summa Theologiae I, q. 19, a. 3.). Consider, for example, that when we choose to do something we do it only insofar as we seek to acquire something that we perceive will in some way perfect, satisfy, or fulfill us. In other words, we perceive it as good for us—that which will help us to be happy. This insight was expressed in St. Thomas Aquinas’s teaching that whatever we choose we choose sub specie boni—under the aspect of good (ST I-II, q. 8, a. 1.). Consequently, the desire for happiness is at the heart of everything that we do and every decision we make. It determines the people we enter friendship with, the person we choose to marry, the career that we pursue, the associations we associate with, the groups we belong to, and everything else of relevance in life. Given that our desire for happiness is so bound up with how we live our life as human beings, our view of happiness will determine whether we think our lives have meaning, whether our lives are a success, and whether our life is even worth living. In short, our view of happiness can either make us or break us. As such, it’s imperative that we take the happiness question seriously and inquire as to what happiness is. For the ancient Greek philosopher, Aristotle, and medieval philosopher, Thomas Aquinas, happiness is rooted in our nature as human beings. For them, happiness is best understood as human flourishing—the perfection of our human nature. Such perfection comes about when the goods to which our nature directs us are achieved—the goods relevant to both our physical and spiritual wellbeing. Acquiring such goods constitutes the good life—man fully alive. The quest for happiness, then, is the quest to discover the goods that really perfect us as human beings. What are those goods? That’s a topic for another time.