  Watermarks should be introduced in the natural language outputs of AI systems
in order to maintain the distinction between human and machine-generated text.
The ethical imperative to not blur this distinction arises from the asemantic
nature of large language models and from human projections of emotional and
cognitive states on machines, possibly leading to manipulation, spreading
falsehoods or emotional distress. Enforcing this distinction requires
unintrusive, yet easily accessible marks of the machine origin. We propose to
implement a code based on equidistant letter sequences. While no such code
exists in human-written texts, its appearance in machine-generated ones would
prove helpful for ethical reasons.
