system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does washing knives in the dishwasher dull them?
gpt
Sharp knives narrow to a very thin and deceptively delicate edge. Knives which are in the dishwasher will be exposed to water jets from various directions which can cause them to shift in whatever is holding them, causing the blade to impact something that would dull the blade edge.

Beyond that, some dishwasher detergents contain actual abrasives. This fine grit when blown around the washer will help strip off food particles but will also slightly abrade the blade edge such that it becomes dull.