Intelligence is the ability of the human body to organize its own contours in a way that corresponds to the objective contours of the world.
Evald illyenkov.
And yes, the mind is part of the body, thus thinking consists of an action of organization to the contours of the world
What about animals?
To me best definition of intelligence is:
It's the ability to:
- Solve problems
- Develop novel insightful ideas, patterns and conclusions. Have to add that since they might not immediately solve a problem, although they might help solve a problem down the line. Example could be a comedian coming up with a clever original story. It doesn't really "solve a problem" directly, but it's intelligent.
The more you are capable of either of the two above, the more intelligent you are. Anything that is able to do the above, is intelligent at least to some extent, but how intelligent depends on how much it's able to do.
It's not about excluding animals, the quote was in the context of talking about people. You can apply the very same thing to any entity