D&C 77 and the Age of the Earth

In response to my article on Science and (LDS) Religion where I advocate the idea that LDS religion is compatible with science and with the concept of an old earth, I have received an inquiry about Doctrine and Covenants 77 and the age of the earth. At first glance, D&C 77 seems to say that the earth is 7,000 years old. But this is not the case. A good discussion of this verse can be found in a book I just picked up and highly recommend, Can Science Be Faith-Promoting? (Salt Lake City: Blue Ribbon Books, 2001, 252 pages) by Dr. Sterling B. Talmage, son of the late Apostle and scientist, James E. Talmage. In his discussion (pp. 174-176), he examines the words uses in D&C 77:6:

What are we to understand by the book which John saw, which was sealed on the back with seven seals?

A. We are to understand that it contains the revealed will, mysteries, and the works of God; the hidden things of his economy concerning this earth during the seven thousand years of its continuance, or its temporal existence.

The time covered by the seven seals refers to things of God's "economy" during this period of "continuance." He finds "economy" is not used elsewhere in the scriptures, but does have a theological definition in the dictionary (Practical Standard Dictionary, p. 369):

6. Theol. A method of divine management of human affairs, or a system of laws and regulations, rites, and ceremonies; the holy scheme of creation and redemption; specif., and particular method of divine government, as the Mosaic economy.

Talmage then suggests that "economy" may refer to God's dealings with men on earth rather than with the earth itself, and the hidden things in this regard refer to things that have been revealed or yet to be revealed (it would seem that "mysteries" would fit well here).

He then considers the word "continuance" and notes that its usage in the scriptures (Ps. 139:16, Is. 64:5, and Rom. 2:7) does not indicate totality of duration, but progress in advance of an earlier stage. The first volume of a magazine is not a continuance, for example, but later volumes can be. His examination of the dictionary leads to the conclusion that "continuance" refers to the current time period with an unspecified time period preceding it.

The final term he considers is "temporal." The dictionary allows "temporal" to have the same connotation as "temporary" or "current," but he finds no evidence that it should be synonymous with "physical" or "material." He finds its most usual or appropriate meaning to be "pertaining to affairs of the present life."

The three terms that Talmage analyzes harmonize with each other and all point to the conclusions that D&C 77 refers to God's dealing with man under the present time period (the collection of dispensations of the past several thousand years), and does not say anything about the time of the Creation or age of the earth, or even the antiquity of other humans or humanoids.