当系统运转顺畅时，它对你是透明的 -- 你只看见输出，看不见内部 (black box) 当系统出故障时，它的内部结构才会暴露出来 (as it requires you to look "into" it) 哲学家海德格尔叫它 **"故障显现"（breakdown）**：工具在正常使用时是隐形的，只有当它坏掉，你才真正"看见"它。 > “Nearly everything worth maintaining is nested in something larger, even more worth maintaining.” Struggling with broken systems is how we come to understand them — and care about fixing them. the struggle is part of how we learn what's broken — and why it matters [[Maintenance is how human connect with and understand the world]]