| Cogito ergo sum|
Logic and rhetoric
Wish in one hand, shit in the other, see which one fills up first—Steven King
A moralistic fallacy (closely related to wishful thinking) is a logical fallacy that occurs when someone asserts that what is Moral, or the way things should be, is in fact how they naturally are, and that anything that is "immoral" is "unnatural".
While cognitive dissonance (e.g. as in the fable of The Fox and the Grapes) describes the suffering experienced when holding an internally inconsistent worldview, utilizers of the moralistic fallacy solve this discomfort by simply overriding everything with how it should be, case closed — ta-daa, suddenly the world adds up.
- Appeal to Hope
- Wishful Thinking
Wanting something to be true is irrelevant to its truth. We generally want the world to be a Moral and Just place, but the harsh reality is that the world isn't naturally Moral. Just as David Hume pointed out that we can't derive what is Moral from the "natural order" alone, we also can't derive the "natural order" from what we (often arbitrarily) determine to be Moral. What we have a moral imperative to do is not strictly tied to how the world naturally works, and many, many bad things that people do are in fact extremely natural. Morality isn't some intrinsic force in the universe, but rather, Morality is Humanity working to overcome our own more self-destructive tendencies.
Don't believe us? Toddlers can't will cookies into existence; 6 million Jews' belief in human rights didn't seem to do much.
The term "moralistic fallacy" was coined by biologist Bernard Davis, who was upset about how, in his opinion at least, biology was unable to do significant research into behavioral genetics. The reason being that on one side, racists and the like are always searching for some way to hide their bigotry behind science; "we aren't racist, we're race realist and have this poorly defined study to back us up!" It's to the point where if someone starts up about group genetics and behavior/intelligence/whatever, 11 times out 10 you are going to hear a racist diatribe. Never mind that if any "race" is the "master", it's the mixed race; there are reasons that most species reproduce through sex and not cloning.
Counter to this, and the focus of Davis's ire, are progressives and equal rights activists who insist that because bigotry is wrong, anything that could possibly be used to support the idea that any differences between people are inherent rather than social or environmental must also be wrong, including behavioral genetics. It certainly didn't help that the same guy who founded behavioral genetics is more famous for creating eugenics. So while various racists commit moralistic fallacies with regards to biology and genetics, progressives may commit the moralistic fallacy and impede research whether it's for the "right" reasons or not.
- PETA and other animal rights activists have argued that milk is less healthy than alcohol, and even causes autism in the unborn.
- To many vegans, eating meat is an immoral act. Some will go so far as to claim that humans don't naturally eat or even desire meat or that our digestive systems didn't evolve to handle it, which if true would cause meat eaters to be emaciated rather than obese, though in fairness, humans really didn't evolve to eat an unlimited quantity of meat. Most people really would be a tad healthier if they ate a bit less, even if they don't have to cut meat out of their diet entirely.
- Inversely, carnivore dieters on the (alt-)right claim that humans, especially men, don't naturally eat plants or that our digestive systems can't handle them, at least not noticeably better than they can handle meat, which if true in the strictest sense would cause male plant eaters to have low testosterone from emaciation rather than digesting plants properly (although they also claim that soy isoflavones are secretly human estrogen without accounting for why a plant would naturally have a human hormone). Apart from the comparison being unfair because an animal digestive system can't use all the same pieces to handle both plants and meat if it has pieces for handling both, the claim mocks men who hold different values. The truth is that Humans are some of the most adaptable creatures on the planet, and even with relatively primitive technology, can survive in just about every terrestrial biome on the planet, and that includes the differences in diet. Imagine if there was a species of Rhino that could survive in deserts, forests, mountains, swamps, tundra, jungle, flood plains, grasslands, and also survive on a diet that's almost entirely meat, or a diet almost entirely plant-based, all in the same species that was still capable of interbreeding rather than becoming separate species.
- Some feminists may go beyond merely saying men and women ought to have equal opportunities in finding a way to contribute to society, to asserting that there are no differences in the first place, or that women do everything better.
- Infidelity is viewed as immoral by many, and so it must not be natural to desire other people than one's monogamous partner. Being attracted to multiple people at the same time is viewed as a form of deviance, rather than a natural desire of humans. Likewise, just because it may be natural to desire someone other than your spouse does not mean that cheating on your spouse is in any way moral.
- Some fundamentalists' statements about Darwinism follow this thinking, as does Soviet Communism, oddly.
- Homosexuality deserves extra mention. Fundies will view it as immoral, therefore homosexuals can't naturally be attracted to each other; there must be some nefarious force or group corrupting people. A cult of homosexuals who recruit others? Satan? Hollywood Liberals? Regardless, it "can't" be an immutable characteristic of people, so it must be "curable" with Conversion therapy or other BS.
- The vast bulk of alternative medicine (especially of the "indigenous" variety) follows this line of logic.
The concern has been that evidence contradicting such moral values will lead to people justifying this behavior, since it is "natural". While understandable, this has led to instances in which research that contradicts them caused people uncomfortable with it to engage in denialism. In the realm of religion it can take the form, "God is good, therefore He does not support X, which I view as bad." Alternately, it is possible for an atheist to make the opposite fallacious argument (as they are alleged to by some theists) that "I view God (or His commands) to be bad, therefore He does not exist."
In public policy
Wishful thinking may characterize popular consensus on other important public policy issues. For example, American space policy is now in the grip of the belief that private firms will finance the exploration of outer space. For a while this seemed unlikely, but felt good because it offered an escape from spending the large sums necessary for human space exploration. (However, it should be noted that, while space exploration is expensive, it forms a much smaller part of the national budget than most people realize: NASA's share in the US budget comes to around 0.6%, down from around 5% during the height of the Apollo program.)
It should be stated, however, that this example may in fact become a reality. Elon Musk's SpaceX appears on the verge of bringing reliable, reusable rockets into the mainstream, promising to cut the cost of space missions by orders of magnitude. Other firms including Planetary Resources and Deep Space Industries were founded with the intent to (eventually) mine asteroids and ship the products around the Solar System; even if reusable rockets become commonplace, building space hardware without having to rocket raw materials out of a gravity well is hoped to be substantially cheaper.
If this actually happens, we'll need a new example. Humans being the delirious life forms we are, though, there should be no shortage.
Positive outcome bias
Positive thinking versus wishful thinking
Wishful thinking is not the same thing as "positive thinking", or the idea that by thinking positively, one will experience better outcomes. Thinking positively can help a person achieve a particular goal, in much the same way that thinking negatively can be a demotivating factor; thinking positively can conceivably help someone to maintain their focus on getting some task done. Wishful thinking, on the other hand, is more about changing reality to match one's perceptions, or thinking that reality would be swayed by what you think.
An apt analogy can be found in medicine. Thinking positively about a course of treatment can improve a patient's outlook on life, helping the patient to feel better and maybe even having a placebo effect. Meanwhile, wishful thinking would entail denying that one had an illness, or that God would cure it, or that it will simply get better on its own, and assuming it would go away just because of that.
- Appeal to consequences
- Appeal to emotion
- Appeal to nature: What is natural is goodz
- Escape to the future
- Hume's law: The is/ought problem
- Law of Attraction
- Magical thinking
- Name it and claim it, a.k.a., the prosperity gospel
- Solferino fallacy: War is natural, and therefore good.
- Willful ignorance
- Wishful thinking
- Word magic
- Logical Fallacies.info on the moralistic fallacy.
- Religions Wiki on the moralistic fallacy.
- Fallacy Files 
- Internet Encyclopedia of Philosophy 
- Wikipedia 
- Bruce Thompson 
- Global Tester 
- Skeptic's Dictionary 
- Gordon, Hanks, & Zhu 
- Neo-Lysenkoism, IQ, and the press
- Is Beer Healthier Than Milk? (September 7, 2016) PETA (archived from September 9, 2016).
- Got Autism? Learn About the Link Between Dairy Products and the Disease PETA (archived from December 7, 2013).
- SpaceX's successful landings Space, April 8, 2016
- Academic Referee Bias