5.1 Why neural networks?5.1.1 Neural networks for words5.1.2 Neurons as feature engineers5.1.3 Biological neurons5.1.4 Perceptron5.1.5 A Python perceptron5.2 An example logistic neuron5.2.1 The logistics of clickbait5.2.2 Sex education5.2.3 Pronouns, gender, and sex5.2.4 Sex logistics5.2.5 A sleek, new PyTorch neuron5.3 Skiing down the error slope5.3.1 Off the chair lift, onto the slope: Gradient descent and local minima5.3.2 Shaking things up: Stochastic gradient descent5.4 Test yourselfSummary