DEEP LEARNING Adding hidden layers to our neural network gets us a more sophisticated algorithm, one that’s able to judge sandwiches as more than the sum of their ingredients. In this chapter, we’ve only added one hidden layer, but real-world neural networks often have several. Each new layer means a new way to combine the insights from the previous layer—at higher and higher levels of complexity, we hope. This approach—lots of hidden layers for lots of complexity—is known as deep learning.
