(Scroll down if you see a big white space, I haven't figured out how to eliminate it.)
View of Evolution and View of Creationism
View of Evolution
* Less than 0.5%
I commend Gallup for publishing this 2-dimensional table. In press releases, pollsters rarely show data along more than one dimension at a time, which makes it difficult to discern any correlations. And there are some amazing finds in this table.
If you sum up the numbers in the four cells in the top left quadrant, you find that 23% of Americans say that both evolution and creationism are definitely or probably true. (Actually, Gallup states the fraction as 24%, probably correcting for rounding errors.) It is logically possible to disbelieve both (e. g., one can believe that non-divine space aliens brought us to Earth), and 3% of respondents took that position, but how do you believe both theories? Was the question asked in a way that presented them as compatible? Let's see:
Next, we'd like to ask about your views on two different explanations for the origin and development of life on earth. Do you think -- [ITEMS ROTATED] -- is -- [ROTATED: definitely true, probably true, probably false, (or) definitely false]?
A. Evolution, that is, the idea that human beings developed over millions of years from less advanced forms of life
B. Creationism, that is, the idea that God created human beings pretty much in their present form at one time within the last 10,000 years
While the question does leave a lot to be desired (introduction talks about the origins of life on earth, but both options mention the development of human beings), it is impossible to interpret the two options as logically compatible. You can't say both are true without violating the laws of logic. So, 24% of respondents made no sense!?
It is worse than that, actually. If you consider one of the theories to be "definitely true", you must, logically, consider the other "definitely false". So everything above and to the left of the diagonal is logically inconsistent. That is 6 cells, not just 4, and the percentages add up to 31%. Almost a third of respondents couldn't answer the two questions without contradicting themselves!
Much to my chagrin, the evolutionists, as a whole, did no better in the logic department than the creationists: in both camps, about a third of "definitely true" supporters and more than half of the "probably true" supporters violated logic. Worse yet, as there are fewer "definitely true" evolutionists, the total percentage of logic violators is actually somewhat higher among evolutionists (49% to 45%).
What could be the reasons for such massive inconsistency?
Some people may genuinely contradict themselves, but I doubt that they account for a significant part of the 31% logically challenged.
A lot more people could have misunderstood the questions. Too much information may have been packed into those two questions, and a rather narrow version of creationism is described (young-earth creationism). A lot of people actually believe in both evolution and creation to some extent, just not in the variants described. (More about those people in a bit.) If they didn't listen to the questions past the first words, they might have thought they agreed with both.
The results could be biased if people tend to give answers they think will please the investigator or sound agreeable. Since there was no neutral option (distinct from "no opinion") given, those who really think that "the jury is still out" had to choose between a weak positive and a weak negative opinion. And the actual responses break overwhelmingly in favor of weak positives: 35-16 for evolution, 27-16 for creation. As for the options available to true fence-sitters, double "probably true" beats double "probably false" 14 to 1. I think this bias accounts for something, but it is hard to believe that there could be so many people sitting on the fence without even leaning to one side.
Finally, the explanation may be in the people whose views differ from either option, but have something in common with both:
A separate Gallup Poll trend question -- also asked in May -- gave Americans three choices about human beings' origins. Responses to this question found that 43% of Americans choose the alternative closest to the creationist perspective, that "God created human beings pretty much in their present form at one time within the last 10,000 years or so." A substantial 38% say human beings evolved, but with God guiding the process. Another 14% favored an interpretation of evolution arguing that God had no part in the process, leaving a total of 52% who say humans evolved with or without God's direction.
52% is remarkably close to the 53% who, in the two-way poll, say evolution is definitely or probably true, and one would expect that theistic evolutionists would choose one of those answers. On the other hand, the two theistic views (creation and theistic evolution) account for 81% of respondents, which far exceeds the 66% that said creation was definitely or probably true. But that, too, is to be expected, because theistic evolution and young-earth creationism are mutually exclusive. The surprising result is not that the support for creationism doesn't gain 38% from the 3-way to the 2-way poll, but that it gains anything substantial, let alone 23%.
So, do the theistic evolutionists explain the supporters of both views? Not entirely - for example, fewer people are in the "definitely evolution, definitely not creation" corner than support non-theistic evolution in the 3-way poll - but a reasonable case can be made that most of the strange, illogical answers are due to theistic evolutionists. If about 60% of them didn't pay attention to the full description of creation, and heard only the part they agreed with ("God created human beings"), practically all of the double-support puzzle would be explained.
If it is implausible (and even offensive to the theistic evolutionist group) that 60% would have attention span shorter than 5 seconds, there is an almost equivalent, but more plausible and, possibly, less condescending explanation. Most people have a really hard time thinking in terms of probabilities, and a statement like "A is probably true" means to them something very different from what it means to me or to Gallup pollsters. I would automatically read it as "The probability that A is true is between 50% and 95%". (The upper limit of the range is the only unclear piece - should it be 90%? Or 99%? Maybe 99.99%?) But such numerical probabilities would mean nothing to many people; to make sense of the original statement, they may need to reinterpret it as "I somewhat agree that A is true." Of course, it means something quite different, but if your language doesn't have words for certain concepts, you make do with the best translation you can find (or make up).
If I am on the right track, there was a miscommunication between the pollsters and a substantial number of respondents. Those respondents changed the meanings of the answers: "definitely true" became "I agree strongly", "probably true" became "I agree somewhat" and so on. Such people could hold any of the substantive views probed by the poll; in most cases, there won't be any effect on the results. But take a theistic evolutionist who has to evaluate creationism. He believes that God created humans, by guiding the evolution process or intervening in it, but doesn't believe it happened as recently as literary interpretations of Genesis suggest. If he understands the options given by the poll, he will say that creation is definitely false (or probably false, if he is not so sure that Genesis is not literally true). But if he reinterprets the options as I think is likely, he can easily choose the option that, to him, sounds like "I agree somewhat", even if he is absolutely sure that the earth is billions of years old and that humans have emerged hundreds of thousands of years ago. After all, how significant are some numbers compared to God's act of creation?
To summarize, if 60% of all people can't think probabilistically, and that percentage is about the same among theistic evolutionists, the misunderstanding between pollsters and respondents can account for most of the anomalous result in the 2-way poll.
It's still depressing. A third of Americans contradict themselves, and most of those are unaware that they do.