The Limits of Intelligence

The Limits of Intelligence

The laws of physics may well prevent the human brain from evolving into an ever more powerful thinking machine

By Douglas Fox  | 

Image: Photograph by Adam Voorhes

In Brief

• Human intelligence may be close to its evolutionary limit. Various lines of research suggest that most of the tweaks that could make us smarter would hit limits set by the laws of physics.
• Brain size, for instance, helps up to a point but carries diminishing returns: brains become energy-hungry and slow. Better “wiring” across the brain also would consume energy and take up a disproportionate amount of space.
• Making wires thinner would hit thermodynamic limitations similar to those that affect transistors in computer chips: communication would get noisy.
• Humans, however, might still achieve higher intelligence collectively. And technology, from writing to the Internet, enables us to expand our mind outside the confines of our body.