René Magritte painted a pipe and wrote "Ceci n'est pas une pipe" beneath it. This is not a pipe. We print "shirt" on a shirt and mean the opposite. This is exactly a shirt. Nothing more, nothing less. Magritte was making a point about representation and reality. We're making shirts. The comparison probably ends there.
But does it? When you wear a shirt that says SHIRT, you're making a statement about statements. You're participating in an ancient philosophical debate about the relationship between signifier and signified, except you're doing it while grabbing coffee or sitting in a Zoom meeting. The shirt becomes both object and label, thing and word, fashion and anti-fashion. It exists in a strange loop of self-reference that would make Douglas Hofstadter proud, if Douglas Hofstadter cared about your wardrobe choices.
The real existential crisis isn't the shirt's—it's everyone else's. "Why does your shirt say shirt?" they ask, as if the answer isn't literally printed on the garment. The question reveals more about the questioner than the questioned. We've become so accustomed to clothing that promises transformation ("Unleash Your Potential"), aspiration ("Just Do It"), or identity ("Cornell Mom") that a shirt simply announcing its shirt-ness feels like a glitch in the matrix.