There are lot of reasons to believe in God, some of these come from the head, which involve sophisticated philosophical reasoning, while others come from the heart.
But here we’ll sum them all up in one straightforward explanation, “the anthropological argument” which argues for the existence of a personal God from the personal nature of human beings.
As personal beings, we are self-aware and rational. We are free to love and make moral decisions. We have longings for meaning and significance. These attributes constitute the essence of what it is to be a person.
The dilemma we face is that we either exist in an environment (the cosmos) which is compatible with these attributes, or we do not. Unless our environment is ultimately itself personal, unless the ultimate context in which we live is self-aware, rational, loving, moral, and purposeful, then our cosmic environment does not at all give an answer to our personhood. In other words, unless there is a personal God who is the ultimate reality within which we exist, then we humans can only be viewed as absurd accidents of nature.
We instinctively assume that reality should be rational, but in the end nature is irrational if there is no overarching mind to it. We instinctively assume that love is the ultimate ideal worth living for, but nature on its own is an indifferent brute process of colliding chemicals. And we instinctively hunger for meaning and purpose. But if our cosmos is ultimately indifferent and purposeless, everything we strive for is ultimately meaningless. Without a personal source for all existence, who we are is both unexplainable and ridiculous.
But how could such a state of affairs ever come about? Where did our longing for something that never existed, and that never could exist come from?
The characteristics of personhood, and the longings which arise from personhood, require that the ultimate cause and context of personhood is also personal. This, at least, is the only rational assumption to make about the cause behind our lives.
Catholics don’t stop there with a belief in a creator-God that is just a theory that we happen to hold to be true. It is in fact a living relationship. Each Catholic comes to believe in God, and to a trust in the sacrifice of Jesus Christ as the only way to make sense of the longings of our personhood. All that the heart longs for is not only given an explanation by a faith in God: it is given its fulfilment in Jesus Christ.