likelihood so automatically because your probability distribution needs to be normalized it's going to have the effect of pushing up the energy of stuff you don't observe but it's very difficult because you get the log of this normalization term the partition function which is generally intractable and so it's very hard to do this so that's called maximum likelihood and which when it's intractable you have to use approximation like variational approximations or or Monte Carlo methods or Markov chain Monte Carlo methods