What the Gap Theory Gets From Genesis, and What It Adds
A popular reading of Genesis says the Bible describes two creations. In the first, God made a perfect world. Satan rebelled, God judged the world, and the earth was left ruined. Genesis 1:2 describes the wreckage. Genesis 1:3 and the six days that follow describe the repair. The reading is called the gap theory, or the ruin-restoration reading, and it has one great attraction: it lets a reader keep a six-day week and still place millions of years, fossils, and animal death in a world before Adam.
The question is not whether the reading can be built. It can. The question is how much of it Genesis states, how much Genesis merely permits, and how much Genesis requires. Those are three different things, and the gap theory depends on running them together.