It is sound judgment to hope that in the not too distant future we shall be competent to understand so simple a thing as a star.

This quote is about wishing for a future where humans have advanced to understand something that seems simple now: a star. Humans could have a greater understanding of stars than we do today, and this quote expresses the hope that this will come to pass in the near future. This hope stems from believing that humans are capable of eventually gaining a greater understanding of stars.