 So if you think my simple energy landscape made sense, you will hopefully agree that there are two things we want to be able to understand and predict. First, how good is it to be in different energy minima? And well, you want to be in the lowest, but does that mean that everything want to be in the lowest? No. We already proved that last lecture, which is for a special case. Second, if there are barriers, how fast can we get across them? So this is related to two concepts that I'm going to get back to at the end of this lecture. The first one has to do with stability. Where are you stable and what do we mean by stability? The second one has to do with kinetics, that is, how fast do changes in a system happen? They're very much related and all they're now I'm going to argue that this one is related to minima, but not just the global minima, the local minima in the free energy landscape, while the second one here is related to the barriers between them. So stability and kinetics. But to understand this, we're going to need to be a bit more proper about deriving the Boltzmann distribution.