Texas sharpshooter fallacy
From RationalWiki
The Texas sharpshooter fallacy is using the same data to both construct and test a hypothesis. Its name comes from a parable where a Texan fires his gun at the side of a barn, then paints a target around the shots and claims to be a sharpshooter. A hypothesis must be constructed before data is collected based on that hypothesis. If one data set is used to construct a hypothesis, then a new data set must be generated (ideally, in a different way, based on predictions made by the hypothesis) to test it.
Much of young earth creationism relies on this form of post hoc reasoning. This is most clearly demonstrated in fundamentalist Christians' discussions of how the flood created geologic structures. Their ideas rely on finding data and constructing a hypothesis around that data, with no further testing of these ideas after this construction. This is a clear example of this particular fallacy.
[edit] Example
- A million-participant raffle was drawn, and Joe was found to be the winner. Afterwards, someone points out that the odds of Joe winning are a million to one, and thus, he couldn't have won randomly and must have cheated. Of course, the chances of anyone else winning was also a million to one, and this person could have accused everyone of cheating. However, the chances of somebody winning is 100% guaranteed. In this case, Joe lucked out. Somebody had to luck out.
Similarly, creationist/ID arguments claim that the chances of a protein molecule forming "randomly", or a cell forming "randomly" via abiogenesis, or the universe forming "randomly" into what we see today are incredibly low, and thus it must have been designed. However, just as somebody was bound to win the raffle, some universe, and some cluster of atoms and molecules was bound to form. It just so happens that Joe won, and it just so happens that our universe won (i.e., formed), and the atoms and molecules clustered in the form of proteins and life forms we see today. This argument is also extremely faulty in that it doesn't acknowledge that physical processes are not random, but are guided by the laws of physics, chemistry, and eventually, biology: evolution via variation and natural selection.
