gradient you don't have a handle on how do you need to change each individual weight all you can do is basically random walk and observe what happens and if the random walk is you know turns out to be good you go more into that direction of that random walk so it's sort of a sort of a poor poor man's gradient method in these evolutionary methods again completely independent of what we learn you can use the evolution evolutionary method to learn the fixed weights and that's what actually what happens in the table i've shown you