Nirvana Fallacy
An informal fallacy where a realistic [insert something, someone, solution, etc. here] is compared to an idealized, unrealistic alternative. This is done in an attempt to dismiss or diminish the realistic proposition. Further, this can also refer to the scenario where a perfect solution* is assumed in a given scenario, when in reality, such a solution may not actually exist. Or, that the solution should be rejected on the grounds that the solution wouldn't solve the problem completely.
By creating a false dichotomy between an implausible, clearly advantageous option, the person using this fallacy can attack any opposing idea as being inferior and, hence, justifying a dismissal. Specifically, this fallacy occurs when the choice is between one realistic, achievable possibility and another unrealistic, but “superior” solution.
*This scenario is known as the perfect solution fallacy, which is a closely related concept. In fact, they are so closely related that the nuance between the two is almost nonexistent and they are often used interchangeably. This fallacy is an example of binary thinking, which is when a person fails to see the complexity or nuance in a given problem and, as a result, reduces the situation to a pair of extremes.
Logical Form
A is presented as a solution to a given problem.
B is presented as an unrealistic, idealized solution.
Thus, A is dismissed as being an inferior solution to B.
Examples
The following abbreviations are used in the examples below:
PN = The Nth premise for N = 1,2,3,…. (e.g., P1 is the first premise, P2 is the second premise, etc.)
C = Conclusion
1) This type of fallacy is often encountered in politics when individuals are discussing prospective candidates. For example:
P1: Candidate X has many admirable qualities and is definitely a front-runner for President. However, she's a liar, accepts money from lobbyists, is too old, and used to oppose gay marriage.
P2: The Presidency is supposed to be held by someone who embodies the morals and virtues of this nation. They would work for the people and not the corporations. They should always tell the truth and stand firm on their positions on key issues throughout their political career.
C: Therefore, she is unfit to be President.
Explanation: While I agree with the sentiments that the President of a country should embody the morals and virtues of the nation, at the end of the day, the office of Presidency is held by a human being who has flaws like the rest of us. Further, everyone lies from time to time; politicians are no exception, so to expect this person to be free from ever telling a lie is unrealistic. More realistic metrics would consider the frequency and severity of a politician's lies.
This argument is using the nirvana fallacy to frame a presidential candidate as immoral and unfit for the office by comparing her to an unrealistic idealization of who the office of President should be occupied by. This argument clearly isn't grounded in reality.
2) Besides cherry-picking and using the appeal to nature fallacy, I have often encountered the nirvana fallacy* being used by those who harbor anti-vaccine sentiments for safety reasons. For example:
P1: While it is true that vaccines have been a great benefit to society, there are still the possibility of side effects. Plus, they aren't even 100% effective against the disease(s) that you're getting vaccinated against.
P2: A medical intervention of this nature that is on the verge of being mandated by Governments, should be free from side effects and 100% effective.
C: Thus, vaccines should be avoided until this can be consistently demonstrated.
Explanation: Vaccines, like all efficacious medical interventions, will never achieve 100% effectiveness and/or be free from all side effects; this is an unrealistic expectation. The scientific community has done their best to minimize side effects while maximizing the efficacy of the vaccines, but neither has achieved 100% in either category to date and we shouldn't expect to given the diversity and complexity associated with each member of our society. All that said, vaccines are still one of the best medical technologies available to combat infectious disease and even cancer. Ample scientific studies are conducted prior to widespread adoption that demonstrates that the benefits of the vaccine far outweigh the risks [1].
* If we were to acknowledge the nuance between the nirvana fallacy and the perfect solution fallacy, this example would fall into the perfect solution category.
3)
P1: Renewable energy technologies (i.e., wind, solar, geothermal, etc.), while better for the environment than fossil fuels, pale in comparison to the energy windfall that “zero-point energy” would provide for us.
C: Therefore, we should really be focusing on developing that technology instead of wasting our time on renewable energy.
Explanation: “Zero-point energy” is the vacuum fluctuations of free space (i.e., there are particle, ant-particle pairs constantly popping in and out of existence everywhere in space), which has been experimentally verified through what is known as the Casimir Effect [2]. However, to date, no one has been able to derive a way to extract energy from the vacuum as it is not clear that it's even possible. Even if it were possible, any net gain would amount to what's known as “free energy.”
One of the fundamental tenets of physics is that “energy is neither created nor destroyed,” which is a way of saying that energy isn't free. People have speculated about free energy for centuries, but the problem is that if something like this were to exist, it would directly contradict everything we know about physics. Thus, this argument is comparing a realistic solution to an unrealistic solution that contradicts the laws of physics. This is clearly nonsensical.
4) Beyond the slippery slope fallacy, I have often observed gun proponents, who are completely against any sort of new regulation, use flawed arguments containing the nirvana fallacy*. For example:
P1: Implementing any sort of new gun regulation is not going to work as the bad guys will still be able to get their hands on guns if they want to.
C: Ergo, gun regulation is not going to work.
Explanation: Complete eradication of criminal activity surrounding gun violence is not what is expected. As hard as we try, complete eradication of gun violence is not going to happen as it's an unrealistic goal. However, this doesn't mean that we can't further reduce the statistics of gun-related violence by implementing new laws in this area. Again, 100% may not be achievable, but this isn't a good argument for not implementing new laws in an attempt to improve society.
*Once again, this example technically falls into the the perfect solution category.
Conclusion
As is always the case, if you find yourself confronted with this fallacy in everyday discourse, it is important to remember that it renders the argument bad and should be rejected. What is more, if you find yourself using this fallacy within one of your own arguments, as an individual who ascribes to the philosophy of Critical Thinking, you must replace it with a good argument.
References
[1] Vaccine Safety. Retrieved from Vaccines.gov.
[2] Casimir Effect. Retrieved from Wikipedia.