Wishful thinking is both a cognitive bias and a logical fallacy. It consists of believing something, or believing something to be more likely than it in fact is, because one wants it to be true.
As a logical fallacy, it it similar to the appeal to emotion, except that the appeal is to one's own emotion rather than only to the emotions of the audience. The fallacy makes a desire for the conclusion to be a premise; that is, it takes the following form:
- I want P to be true.
- Therefore, P.
A person engaging in wishful thinking almost never states it so bluntly, however. Instead, that person may cherry-pick the evidence or otherwise distort reality to support the desired conclusion.
There is also reverse wishful thinking, which is Murphy's law as a cognitive bias.
- Atheists engage in wishful thinking when they disbelieve in God because they do not want Him to exist, rather than because they have any direct evidence for the nonexistence of God.
- Homosexuals engage in wishful thinking when they accuse those who oppose and criticize homosexuality and homosexual "marriage" of being "homophobes" and "secretly gay" because, despite having no evidence to prove their claims, they want to believe that their opponents are "self-hating homosexuals", even though those homosexuals who make such accusations are not mind-readers, and they delude themselves into thinking that their opponents are the "opposite" of what they really are because those homosexuals do not want to believe that there is no such thing as "homophobia" or that their opponents have legitimate reasons for not supporting or agreeing with the homosexual lifestyle and its resulting consequences. They also completely ignore the copious evidence of the harms caused by same-sex "marriage" to both individuals and society.
- Believers in discredited scientific theories such as evolution and global warming cling to their beliefs for the same reason.