A few questions arose, which are related to ANN modelling.

First of all, is it possible to determine the number of hidden layers at the beginning and the ANN itself changes this number on its own to optimize the results?

Second, in a supervised training phase, an expert delivers input-result-pairs to the ANN. Will the expert usually take a look at the weights the system proposed or is it hidden / not interesting for the expert?

Third, in an unsupervised training phase, only input elements are delivered to the system. How does the system optimize the weights or it's structure if there is no result for a comparison?

Thanks in advance for some clarification and hints.