What's the meaning of this quote?

This quote emphasizes the way in which some universal truth suddenly comes into focus from the point of view of that character. From his point of view the world keep moving - "relentless circling" - and there is a darkness that cannot be understood or changed - "implacable." We get the picture of dogs pulling the sun across the sky but they are "blind" and thus are unable to understand what they are doing. Life is like the two hunted animals hiding from the pursuer knowing that the cover will probably reveal them eventually. Everything about the world is temporary, "borrowed" for only a short period of time.

The quote is about the despair and hopelessness the father feels at the doomed situation he and his son are facing.

The Earth and the blind dogs of the sun in thier running are the planets in thier endless orbits. The universe is godless and unthinking and as such there is no salvation coming, things are as they are and will not change.

It mentions the 'intestate earth' meaning the earth has died and has nothing left of use to pass on to an all but dead human race. The game is up!

The two hunted animals are the father and his son, the references to 'borrowed time, world, and eyes' are references on the fact that the end is likely near. Borrowed time and world, the world will soon be lost to them and borrowed eyes meaning that after thier deaths their bodies will decompose and return to the fabric of the earth.

Pretty gloomy stuff. This is all taking place in the fathers thoughts at that time though, at the end of the book we find out that there is a small glimmer of hope left.