You might want to spell out what "digital intelligence" means earlier in the piece. E.g., "by digital intelligence we mean something that, like humans, can solve a wide range of problems (not just in one narrow domain like Watson), and that, unlike humans, can be run on a computer as software". In fact, "software intelligence" might be a more transparent term.

This paragraph:

To count as a "digital intelligence," an artificial agent must have at least a human-level general capacity3 to achieve its goals in a wide range of environments, including novel ones.

threw me off at first because the word "artificial" suggested it meant artificial intelligence in the sense of footnote 2.

The split into transparent and opaque as top-level "kinds of digital intelligence" seems unmotivated at this point, as if you said, "there are three kinds of higher animal: mammals, birds with light feathers, and birds with dark feathers".