New Criticals


First, the generality of the fluctuation theorem extends the second law for macroscopic, irreversible processes. What England has done for replication applies generally to anything we can successfully represent in terms of a macrostate with a corresponding probability distribution of microstates. In plainer language,  the second law already told us that the entropy of the universe must increase during any real process. We now know that in addition, if we can find a way to estimate the probability or rate of a process and the probability or rate of the reverse process, then we can say by how much the entropy of the universe must increase during that process, not just that it must be greater than zero. The full generality of that statement is difficult to appreciate, and I’m still pondering the immense consequences.