The previous summary/evaluation was here.
d. The Gap Theory
Grudem rejects secular evolution, theistic evolution, and in this brief section he rejects the so called "gap theory." The gap theory is the idea that there is a gap of millions of years between Genesis 1:1 and 1:2. So God creates the heavens and earth. Then in verse 2 the earth is without form and void, with darkness.
The gap theory thus pictures two creations, as it were. The fossil record that seems to support evolution would come before Genesis 1:1. Then perhaps Satan's rebellion would take place, leaving the earth without form and void afterwards. Then perhaps 10,000 to 20,000 years ago, God would reorder the world in 6 days. The theory notes that the words for formless and void are used of the land after God's judgment in passages like Isaiah 34:11 and Jeremiah 4:23.
Grudem does not find this argument persuasive. First, he argues that God has not yet created light in Genesis 1:2. The world is still in darkness. Second, he points to what is called the overload fallacy. Just because the Hebrew words for "formless" and "void" in other contexts relate to God's judgment doesn't mean that they always refer to God's judgment.
He provides additional arguments. No other verse indicates this theory. Next, Genesis 1:31 says everything God had made was very good. But in the gap theory, Satan and all manner of demons would be around. Genesis 2:1 seems to imply that the creation of the heavens was part of the six days of creation. Exodus 20:11 seems to say that God created everything in six days.
Finally, God's first creation would seem both incomplete and a failure. God would not have finished with humanity, and the plants and animals before would not have fulfilled God's original purpose, leading to their destruction. But Grudem thinks that this contradicts a God who always accomplishes his purposes.
This discussion is a fascinating snapshot of American church history. When the theory of evolution was gaining currency in the late 1800s, conservative Christians did not immediately reject it. Conservative scholars like B. B. Warfield at least considered it, and although Charles Spurgeon would eventually reject it, he seems to have been more open to it initially.
Throughout the early 20th century, the gap theory was not uncommon in some circles, including among some teachers in my own denomination. Since they largely did not interpret the Bible in context anyway, the gap theory provided a way for them to account for the Fall of Satan while providing space for an older earth. Then in the 1970s, individuals like Henry Morris mounted a strong fundamentalist offensive against evolution, and the gap theory was also a target. The mission to stamp it out among conservative Christians seems to have been quite successful.
On the one hand, Grudem is surely correct that Genesis 1:1 and 1:2 know nothing of the Fall of Satan or an orderly creation that is then destroyed or judged by God. Indeed, Genesis and the Pentateuch in general know nothing of Satan (Genesis does not seem to know yet that the serpent is Satan). None of the Historical Books except 2 Chronicles knows anything of the Satan. Satan appears only three times in the Old Testament--in 2 Chronicles, in Job, and in Zechariah.
Grudem correctly observes that no text in the Old Testament knows anything about such a first and second creation. He correctly reads Genesis 1:31 and 2:1 as the end of a single creation process. We can ignore his strange hyper-Calvinist compulsion to think that God has to finish things in one shot.
Yet, as we have argued, he does not correctly sense the nature of Genesis 1 as something more poetic than exactly literal, as something more in dialog with other creation stories than with anything scientific. Accordingly, as we have also argued, he does not see the most natural translation and reading of Genesis 1:1-2. When God comes to create the world, it is already there as a formless and chaotic, watery mess. In other words, Grudem does not read Genesis literally either, only a little more literally than those who used to believe in the gap theory.