- their eyesight is too poor to read

- their paws are not designed for fine manipulations so they cannot write or type

- their throats and mouths are not nearly as nimble as ours, so they cannot vocally communicate detailed information

Even if there was an Newton-level dog, they wouldn't be able to access the ideas of an earlier Euclid-level dog. Human knowledge is not just about our big brains, we've developed many physical features that make transmission of information far easier than other species.

OTOH dogs do have a good intuitive "common-sense" understanding of arithmetic, geometry, and physics. It is the unique gift of humans that we can formalize and then extend this intuition, but this ability (and intelligence as a whole) relies on nonverbal common sense.