Machine learning is nothing but a means of enabling the computer to have a sophisticated sense of proximity between several things. Let me elaborate that point for you with a few examples. Human vision is very advanced. So much so that we hardly realize what is going on in our brain when we recognize something. For example, do you think about the complex processes running in your brain when you read a handwritten note and recognize that is a letter "a"? Consider the pictures of the letter “a” in Figure 1-1.