They're saying the second law of thermodynamics (in a closed system, entropy always increases) means a complex secret can't be kept for a long period of time: t

They're saying the second law of thermodynamics (in a closed system, entropy always increases) means a complex secret can't be kept for a long period of time: the tendency of life/the world towards chaos means that the truth will inevitably leak out. It's more a poetic application of statistical mechanics than a rigorous one.