The wild concept uses neural net theory to unify quantum and classical mechanics. This is a great jumping-off point for larger philosophical discussions. In a thought-provoking new paper, a physicist suggests the whole universe could be a single neural network—a competing “theory of everything” that could unite quantum and classical mechanics, he says. If this is true—and that’s a really, really Science Photo Library - KTSDESIGNGetty Images What’s a Neural Network? A neural network is what’s called a data structure, which is a shape or format for organizing ideas inside computer hardware. If you’ve ever made a shopping list or written down the steps to complete a task, you’ve made a data structure. If you’ve “opened a ticket” in an IT support system at your job, that ticket probably joined a data structure called a queue. You may have even programmed these structures, too, writing code for stacks, trees, and more.