Many Christians scholars argue this to be the case. Peter Enns, for example, in a recent article, The Firmament of Genesis 1 is Solid but That's not the Point, says, "Genesis 1 and 2 tell the story of creation, and it says things that are at odds with what modern people know to be true...". He asserts that ancient Israelites, like other ancient people, assumed the world was flat, and so it looked like the earth was covered by a solid dome (raqia or firmament of Genesis 1), and the “blue sky” is the “water above” held back by the raqia. Enns gives the following diagram of his conception of biblical cosmology:
A similar view of Genesis cosmology can be found in John Walton's The Lost World of Genesis One. Walton thinks the Israelites so dim-witted that they did not even know that the Sun was further away than flying birds (p.16). Much of the recent promotion of this can be traced to various articles by Paul Seely. Seely contends that the Hebrews were scientifically naive and thus would be influenced by their Babylonian and Egyptian backgrounds to believe that the raqia of Genesis was solid (p.235).
The implications are far-reaching. Enns concludes that God accommodates Himself to the limited scientific knowledge of the time, presumably to convey theological truths. Seely extends such accommodation to many other historical events in Gen.1-11 (Perspectives on Science and Christian Faith 60 (2008):44-47). He contends that the message of Gen.1-11 is theological, not history or science as such. This clearly limits the range of biblical authority. It also raises the obvious problem of how to discern the divine kernel from the accommodated chaff.
Does Genesis 1 in fact reflect ancient cosmology?
1. Let me note first that the above diagram is more a reflection of the ignorance of modern scholars than of ancient civilization. Ancient man was a much keener observer of the night sky than modern desk-bound scholars. They were well aware that the stellar sky rotates daily. Hence it cannot be a solid hemisphere held up by pillars fixed on the earth. Further, they were well aware of months and seasons. Hence the sun and moon were not fixed in a stellar shell. They were also well aware that the sun and moon were much more distant than flying birds.
2. A second difficulty is that ancient cosmology as such does not really go back earlier than about 550 BC, with the advent of Greek science. Before that cosmology was entertwined with mythology, making it very difficult to determine what the ancients actually believed about the nature of the physical universe. Noel K. Weeks ("Cosmology in Historical Context,” Westminster Theological Journal 68.2 (Fall 2006): 283-293)elaborates on this in his detailed critique of Seely.
3. A further difficulty, noted also by Weeks, is that is no uniform pre-modern belief regarding cosmology/mythology. Sumerian, Egyptian, Canaanite and Babylonian mythologies had signficant differences.
4. Much of the evidence for Mesopotamian belief in a flat earth floating on a sea is based on one ancient drawing:
This is the oldest known world map--the Imago Mundi of 6th century BC Babylonia. It shows Babylon on the Euphrates, surrounded by a circular landmass including Assyria and Armenia, surrounded by a "bitter river" (Oceanus).
Note, first, that this map dates much later than the time of Moses (ca 1500 BC). Also, at first sight, it looks similar to medieval world maps, which depicted the land mass of europe-asia-africa surrounded by an ocean. However, the latter is known to be just a 2-d depiction of a spherical earth.
Finally, a closer look shows that the Babylonian map has islands beyond the surrounding ocean. So it is not a complete world map. In sum, this map provides no evidence that ancient people believed in a flat earth.
5. Genesis itself says nothing about a flat earth. Seely's case rests primarily on one word: the raqia (firmament or expanse [ESV]) of Gen.1:7, created to separate the waters beneath from the waters above. This is generally thought to refer to the atmosphere and sky or space. Seely, however, claims that raqia refers to the common pre-modern conception of the sky as a solid dome. Yet the Genesis raqia is clearly not solid. Note first that in Gen.1:8 the raqia is called heaven (shamayim). But birds fly in shamayim (Deut.4:17), so that it can't be solid. Also, the sun, moon, and stars are placed in the raqia (Gen.1:14-18). The sun and moon clearly move at different rates than the stars, of which the Israelites would have been well aware (else there would be no months, seasons or years). Hence the raqia mentioned in Genesis 1 can't be solid.
6. What about the water above the raqia? Calvin thought this referred to clouds; James Jordan believes it refers to the sea of crystal in heaven (Creation in Six Days, p.180). God created more than meets our physical eye.
7. Another interesting line of thought is pursued by Peter Leithart (A House for My Name 2000) , who sees many similarities between Genesis 1 and the building of the temple. God's universe is described as His three-storied house. Also G.K. Beale (The Erosion of Inerrancy in Evangelicalism 2008) contends that Genesis is expressing its theological conceptions of the universe, understood to be a huge temple for God (p.163). Hence the architectural despictions of the temple-house are to be understood figuratively. He argues that Israel's temple is a small model of the cosmos, which is a huge temple. (for more on this see the post Cosmology and Heaven). Beale specifically (pp.196-201) rebuts Seely's notion of a solid raqia.
8. The fact that ancient cosmology is entertwined with mythology should alert us to a further important factor. Unlike modern man, ancient man was well aware of the existence of the supernatural. Ancient man understood that the universe was much broader than the mere three dimensions we normally see. The ancient view of the universe included space for God, heaven, angels, and demons. Modern cosmology, on the other hand, with its materialist reduction of reality, has no place for the supernatural or for heaven. The difficulty, thus, is not that ancient man was one dimension short (i.e., a flat earth) but, rather, that he attempted to depict an extra dimension using 3-d imagery. The multi-dimensional universe of ancient man is bound to be distorted by modern man when interpreted in terms of his truncated 3-d model of reality.
In sum, I conclude that the Bible says very little about the details of physical cosmology beyond the creation of the sky, sun, moon and stars. However, it does point to the existence of a heavenly realm beyond the 3 usual physical dimensions.
It seems to me that the current attempt to read Genesis as accommodation to erroneous ancient pagan cosmology is motivated primarily by the desire to constrain biblical authority so as not to contradict modern secular science. This itself is just another form of accommodation, whereby God's word is tailored to fit human reason.