If you want to teach a child what an elephant looks like, you have an infinite number of options. Take a photo from National Geographic, a stuffed animal of Dumbo, or an elephant keychain; show it to the child; and the next time he sees an object which looks like an elephant he will likely point and say the word. Teaching AI what an elephant looks like is a bit different. To train a machine learning algorithm, you will likely need thousands of elephant images using different perspectives, such as head, tail, and profile. But then, even after ingesting thousands of photos, if you connect your algorithm to a camera and show it a pink elephant keychain, it likely won't recognize it as an elephant.