Informal Fallacy: Appeal to Purity

The Appeal to Purity fallacy, is a logical fallacy where one modifies the definition of a term in an ad hoc (when needed) fashion to exclude a counterexample and protect a general assertion. It is a common logical fallacy where someone dismisses a valid criticism or counterargument by claiming that it does not apply to their position because it is based on a distorted or impure version of that position. In other words, the person making the argument is trying to maintain the purity or perfection of their position by redefining it to exclude any criticisms.

Examples:

1. In the realm of health and wellness, the appeal to purity fallacy can be seen when someone claims that only a certain type of diet or exercise routine is truly effective or beneficial. This argument ignores the individual differences in metabolism, genetics, and lifestyle that may impact the effectiveness of different health practices.
2. One example of the appeal to purity fallacy is when a political candidate claims that their opponent is not a true member of their party because their beliefs are not in line with the party's platform. This argument assumes that only someone who perfectly aligns with the party's principles can be considered a true member, which ignores the possibility of diversity of opinion within the party.
3. In social justice movements, the appeal to purity fallacy can manifest when activists dismiss or condemn others for not following a specific set of rules or guidelines for activism. This disregards the complexity and nuance of social issues and discourages collaboration and solidarity among advocates with different approaches and perspectives.
4. In the business world, the appeal to purity fallacy can be seen when a company dismisses customer complaints by claiming that they are not representative of their overall customer satisfaction. This can lead to a disconnect between a company and its customers and hinder the company's ability to address valid concerns and improve their products or services.
5. In science, this fallacy can manifest when individuals dismiss evidence or researchers that contradict a widely accepted theory or belief, thereby protecting their stance without addressing the substance of the counterargument.
6. If someone states, "No scientist rejects the theory of evolution," and is then presented with a scientist who does, they might retort, "Well, no true scientist rejects evolution." This shifts the goalposts and excludes the counterexample by redefining what it means to be a 'true' scientist. 
7. In economics, this fallacy might manifest in statements such as, "No true economist would ever support a policy that leads to inflation," which dismisses economists who do support such policies as not being 'true' economists. 
8. "A real capitalist would never agree to market regulations," thereby excluding those capitalists who do from the category arbitrarily. 
9. This fallacy is particularly problematic in policy making as it dismisses legitimate diversity of thought and opinion within the field, which is essential for robust economic analysis and policy-making. For instance, if someone claims, "No economist would argue against free trade," and another presents an economist who does, the claimant might retort, "Well, no true economist would argue against free trade." This shifts the goalposts and dismisses valid counterexamples by arbitrarily redefining the criteria. 
10. In economics, this fallacy might appear in debates about market policies, where one might claim that any economist who supports interventionist policies is not a "true" economist. Such a statement disregards the diversity of economic thought and invalidates legitimate professional opinions that differ from the claimant's view.
11. In physiology, one might claim that all healthy individuals have a certain blood pressure range, but when presented with a healthy individual outside of that range, the definition of "healthy" is altered to maintain the original claim.
12. In dentistry, a practitioner might claim that a certain procedure is painless, but when a patient experiences pain, the practitioner might exclude that case by claiming the patient's threshold for pain is unusually low. 
13. In medicine, a treatment might be touted as universally effective, yet when it fails, the failure is rationalized by asserting the patient wasn't suitable for the treatment, thus preserving the claim of universal effectiveness. 
14. In pharmacy, a similar situation may arise when a medication is claimed to be pure and without side effects; however, when side effects are observed, the definition of "purity" might be shifted to exclude those effects.
15. Neurology might see an appeal to purity in the classification of neurological disorders, where atypical cases might be excluded to preserve a theory. 
16. Political discourse is rife with such fallacies, where a politician's actions might be defended by redefining what it means to be a "true" representative of their ideology.  

Conclusion:

It's a defense mechanism to maintain the integrity of an argument by excluding inconvenient truths. The appeal to purity fallacy is a common logical fallacy that can hinder critical thinking, communication, and problem-solving in a variety of contexts. It's crucial to recognize this fallacy as it can close off meaningful dialogue and hinder the pursuit of truth by creating an unrealistic standard that cannot be falsified. Understanding and identifying the "Appeal to Purity" fallacy in these diverse fields can help maintain intellectual honesty and promote more robust and evidence-based discussions.

Points to Ponder:

No true economist would argue against free trade. 

Why there is fallacy of “Appeal to Purity” in this statement?