  A core function of intelligence is grounding, which is the process of
connecting the natural language and abstract knowledge to the internal
representation of the real world in an intelligent being, e.g., a human. Human
cognition is grounded in our sensorimotor experiences in the external world and
subjective feelings in our internal world. We use languages to communicate with
each other and the languages are grounded on our shared sensorimotor
experiences and feelings. Without this shard grounding, it is impossible for us
to understand each other because all natural languages are highly abstract and
are only able to describe a tiny portion of what has happened or is happening
in the real world. Although grounding at high or abstract levels has been
studied in different fields and applications, to our knowledge, limited
systematic work at fine-grained levels has been done. With the rapid progress
of large language models (LLMs), it is imperative that we have a sound
understanding of grounding in order to move to the next level of intelligence.
It is also believed that grounding is necessary for Artificial General
Intelligence (AGI). This paper makes an attempt to systematically study this
problem.
