The brain competes for territory rather than following a fixed blueprint

Eagleman's foundational claim is that brain regions aren't permanently assigned to specific functions by genetics alone; instead, neural territory is won and defended through an ongoing competition for input. A region processes whatever signal reliably arrives at it, and if that signal disappears — through blindness, amputation, or injury — neighboring or even distant regions can gradually encroach on the newly available real estate and repurpose it for their own use.

He illustrates this with cases where the visual cortex of someone blind from an early age becomes active during touch or language tasks, effectively getting recruited by other senses once its usual input, light, is no longer available. The brain, in his framing, resembles a bustling city where unused real estate rapidly gets colonized, not a fixed factory floor with permanently labeled stations.

Takeaway: the brain's architecture reflects an ongoing negotiation for input and relevance, not a rigid map — which is why so much recovery and adaptation after injury remains possible.