One is so sure of so many things. Until one day they become obsolete. One is never aware of one’s luck until dealt a fateful blow. We don't appreciate peace until war breaks out. Everything in life is hanging by a thread.
This art work is based on the German expression "am seidenen Faden hängen" ("hanging by a thread of silk") with the connotation of something very unstable or fragile. The irony is that this silk is especially tear-resistant.
This interpretation is standing in contrast with the expression "in Stein gemeißelt" ("be carved in stone"), which means that something is fixed unchangeably. The word carved in the marble stone is GLÜCK (Happiness or Luck).
In the end, it depends on your own point of view.