Of all the expressions I don’t understand, “thank goodness” is my favorite.
Without any other consideration, however, I’d regard the term a step above mere noise or throat-clearing. Although the first word conveys a sense of gratitude (of course), the expression as a whole is so deprived of meaning that it’s almost equivalent to saying “Thank the slithy toves!”
The consideration that makes it an endearing expression to me is that often it comes from a sense of humility and piety, a sense that God’s name shouldn’t be treated cheaply, something close to the instinct that makes Jews avoid pronouncing the Holy Name. But in Christianity (and most religious people I’ve encountered who say “thank goodness” are Christians), “God” isn’t really God’s name, it’s a title like “Father”, “Creator”, “Redeemer”, “Savior,” “Ancient of Days,” and many others. (In fact, “God” in Christianity refers to the Godhead, or to the three persons of the Trinity—which is why we refer to the Father, the Son or the Holy Spirit when we want to be specific).
Regardless, Christians don’t seem to avoid the word “God” in other contexts, but only when expressing their gratitude for small blessings. But what’s cheap about thanking God when you mean to thank God? If God blesses you a dozen times a day through a dozen different ways, shouldn’t you thank Him every time? Should you only thank Him for big things and shrug off the small things? Wouldn’t it be treating Him cheaply to not thank Him whenever you’re grateful—or to thank something else when you mean to thank God? Do we believe that all good things come from God, or just the really big things? Are the small things too insignificant for Him to notice—or so small that He can’t see them?
Christ at any rate didn’t think it was beyond God’s power to number the hair on our heads. And what does that mean, “thank goodness”? Is “goodness” a person? Does it have a will and could choose to give or withhold blessings? Most of us don’t walk around thanking door handles and seat cushions, after all.
Besides a sense of piety, there are two other motivations I can see for using the expression: force of habit or a desire to avoid the word “God” because one doesn’t believe in God. If all the cool kids say “thank goodness” and you’ve picked up the habit from them, I’d encourage you to revolt against mere popularity and use expressions that make sense. If you’re an atheist, and would sooner not thank someone you don’t believe in, I think that’s fair—but you need to find something better than thanking “goodness.” If not, you’ve simply traded expressing gratitude to a person you don’t believe in to expressing gratitude to a concept (which is no more capable of receiving or accepting your gratitude than is the color blue). However, that’s easier said than done because this is one of the practical problems of atheism. You typically don’t have anyone to thank for the blessings in life—even the really big ones. You can behold the beauty and wonder of the universe, and be filled with a sense of gratitude, but you don’t have anywhere to direct that feeling. This is how G.K. Chesterton put it in his brilliant book Orthodoxy:
The test of all happiness is gratitude; and I felt grateful, though I hardly knew to whom. Children are grateful when Santa Claus puts in their stockings gifts of toys or sweets. Could I not be grateful to Santa Claus when he put in my stockings the gift of two miraculous legs? We thank people for birthday presents of cigars and slippers. Can I thank no one for the birthday present of birth?
With Chesterton, I can only say thank God that I have Someone to thank for the birthday present of birth and for the thousands of other unexpected blessings that make up a life.