e Connectivity: Human neurons typically support several hundred connections (synapses). Moreover, the complex pattern of these connections is very meaningful. (See our next point.) Computer units typically make only a handful of connections, in regular, fixed patterns. e Development (self-assembly with interactive sculpting): The human brain grows its units by cell divisions and orchestrates them into coherent structures by movement and folding. It also proliferates an abundance of connections among the cells. An important part of its sculpting occurs through active processes during infancy and childhood, as the individual interacts with his or her environment. In this process, many connections are winnowed away, while others are strengthened, depending on their effectiveness in use. Thus, the fine structure of the brain is tuned through interaction with the external world—a rich source of information and feedback! e Integration (sensors and actuators): The human brain comes equipped with a variety of sensory organs, notably including its outgrowth eyes, and with versatile actuators, including hands that build, legs that walk, and mouths that speak. Those sensors and actuators are seamlessy integrated into the brain’s information- processing centers, having been honed over millions of years of natural selection. We interpret their raw signals and control their large-scale actions with minimal conscious attention. The flip side is that we don’t know how we do it, and the implementation is opaque. It’s proving surprisingly difficult to reach human standards on these “routine” input-output functions. These advantages of human brains over currently engineered artifacts are profound. Human brains supply an inspiring existence proof, showing us several ways we can get more out of matter. When, if ever, will our engineering catch up? I don’t know for sure, but let me offer some informed opinions. The challenges of three-dimensionality and, to a lesser extent, self