  Despite the surprising power of many modern AI systems that often learn their
own representations, there is significant discontent about their inscrutability
and the attendant problems in their ability to interact with humans. While
alternatives such as neuro-symbolic approaches have been proposed, there is a
lack of consensus on what they are about. There are often two independent
motivations (i) symbols as a lingua franca for human-AI interaction and (ii)
symbols as system-produced abstractions used by the AI system in its internal
reasoning. The jury is still out on whether AI systems will need to use symbols
in their internal reasoning to achieve general intelligence capabilities.
Whatever the answer there is, the need for (human-understandable) symbols in
human-AI interaction seems quite compelling. Symbols, like emotions, may well
not be sine qua non for intelligence per se, but they will be crucial for AI
systems to interact with us humans -- as we can neither turn off our emotions
nor get by without our symbols. In particular, in many human-designed domains,
humans would be interested in providing explicit (symbolic) knowledge and
advice -- and expect machine explanations in kind. This alone requires AI
systems to to maintain a symbolic interface for interaction with humans. In
this blue sky paper, we argue this point of view, and discuss research
directions that need to be pursued to allow for this type of human-AI
interaction.
