This is the fourth of five papers comprising The Semantic Arrow of Time. Parts I-III established that computing's hidden arrow of time is semantic rather than thermodynamic, that bilateral transaction protocols create causal order through a mandatory reflecting phase, and that RDMA's completion semantics implement the FITO category mistake at industrial scale. This paper traces the consequences of the FITO category mistake beyond the data center, into systems people use every day. We examine three domains where forward-only temporal assumptions destroy meaning: file synchronization, where cloud platforms silently delete user content because last-writer-wins cannot represent distributed causality; email, where timestamp-based ordering produces phantom messages, causality violations, and stuck synchronization; and memory--both human and artificial--where reconstructive processes that operate without transactional guarantees produce systematic semantic corruption. In each domain, we identify the same structural pattern: a system that commits state changes forward in time without a reflecting phase, and that therefore cannot distinguish between successful semantic integration and mere temporal succession. The pattern is not coincidental. It is the FITO category mistake operating at different scales: bytes in a NIC buffer, files in a cloud, messages in an inbox, engrams in a hippocampus, tokens in a transformer. We conclude that the semantic arrow of time is violated whenever a system treats the forward flow of information as sufficient evidence of meaning. Part V will show how the Leibniz Bridge provides a unified framework for closing this gap across all five domains.

翻译：本文是《语义时间之箭》系列五篇论文中的第四篇。第一至第三部分已论证：计算中隐藏的时间之箭本质上是语义的而非热力学的；双边事务协议通过强制性的反射阶段创建因果序；而RDMA的完成语义则在工业规模上实现了FITO范畴错误。本文追溯FITO范畴错误在数据中心之外、延伸至日常使用系统中的后果。我们考察了三个领域，其中仅向前的时间假设会破坏意义：文件同步领域，云平台因“最后写入者获胜”机制无法表示分布式因果关系而静默删除用户内容；电子邮件领域，基于时间戳的排序导致幻影消息、因果关系违反及同步停滞；以及记忆领域——包括人类记忆与人工记忆——其中缺乏事务保证的重建过程会导致系统性的语义损坏。在每个领域中，我们都识别出相同的结构模式：系统仅随时间向前提交状态变更而缺乏反射阶段，因而无法区分成功的语义整合与单纯的时间接续。这一模式并非偶然。它是FITO范畴错误在不同尺度上的体现：从NIC缓冲区中的字节、云端文件、收件箱消息，到海马体中的记忆印迹、Transformer中的词元。我们得出结论：每当系统将信息的前向流动视为意义的充分证据时，语义时间之箭即被违背。第五部分将展示莱布尼茨桥如何为弥合这五个领域的鸿沟提供统一框架。