“I don't know whether I was then a man dreaming I was a butterfly, or whether I am now a butterfly, dreaming I am a man.”Zhuangzi · Zhuangzi · -300 · capitolul 2
Any check of reality is made from within one state, so no one can prove which state is real.
Zhuangzi dreams he is a butterfly and, waking, finds he cannot prove which of the two states is the real one. The mechanism is that any verification is performed from within a particular state, and is therefore biased: from inside a dream, the dream is real. Someone who radically changes their life at forty and no longer recognizes the person they were at twenty lives exactly this undecidability.
The card shows that verification is biased because it happens from within a particular state. The next step: undecidability is not a problem to solve, but a position you can live from. If every standpoint is one state among others, you are not obliged to pick one definitive identity. You can treat each version of yourself as a visit, not a verdict. Someone changing careers at forty can say of their twenty-year-old self: that was real, but it is not proof of who I am now. Both states are real from inside themselves, and neither can condemn the other. One question remains: if you cannot prove yourself, what stays stable while everything changes?
Why it matters It loosens the anxiety of a fixed identity: if you cannot prove who you are with absolute certainty, you can rest more easily with change and the unknown.