For centuries, philosophers have noted that between stimulus and response there is a space, and within it lies the freedom to choose our actions. That space represents our agency and humanity—unlike other animals, we can be thoughtful and discerning instead of instinctively reacting. At the individual level, that space is crucial for mental health. Collectively, it’s what gives rise to civilization, allowing us to work together, compromise, and resolve disputes without violence. I fear that space is collapsing. And if we don’t do something about it, the consequences will be dire.