  AlphaGo plays chess and Go in a creative and novel way. It is natural for us
to attribute contents to it, such as that it doesn't view being several pawns
behind, if it has more board space, as bad. The framework introduced in
Cappelen and Dever (2021) provides a way of thinking about the semantics and
the metasemantics of AI content: does AlphaGo entertain contents like this, and
if so, in virtue of what does a given state of the program mean that particular
content? One salient question Cappelen and Dever didn't consider was the
possibility of alien content. Alien content is content that is not or cannot be
expressed by human beings. It's highly plausible that AlphaGo, or any other
sophisticated AI system, expresses alien contents. That this is so, moreover,
is plausibly a metasemantic fact: a fact that has to do with how AI comes to
entertain content in the first place, one that will heed the vastly different
etiology of AI and human content. This chapter explores the question of alien
content in AI from a semantic and metasemantic perspective. It lays out the
logical space of possible responses to the semantic and metasemantic questions
alien content poses, considers whether and how we humans could communicate with
entities who express alien content, and points out that getting clear about
such questions might be important for more 'applied' issues in the philosophy
of AI, such as existential risk and XAI.
