Distinction without a difference is a fallacy that often appears in philosophical or political debate. The basic version of the fallacy occurs when a person prefers, or insists on, one term to a synonymous term, even though there is no substantive difference in meaning between the two. The arguer will typically claim that a nuanced distinction between two terms makes them incompatible as synonyms. While a linguistic distinction may in fact occur, if the generally accepted meaning of both terms are not changed by the distinction, the arguer is creating a logical fallacy. This type of fallacy is frequently an aspect of political arguments.
Any term with exact synonyms can be the source of a distinction without a difference fallacy. If a medical professional insists that being called a “physician” is superior to being called a “doctor” because it is closer to the original Greek term. In modern usage, however, physician and doctor are frequently used synonymously and are not used to differentiate two separate types of medical practitioners. Therefore, claiming that being called a “doctor” is insulting and rude, while being called “physician” is correct and polite is a distinction without a difference, since the meaning of the term is not changed by the word chosen.
Public debates are also notorious for having this fallacy. Opposing sides are notorious for coming up with negative terms that describe the position or policy of an opponent. Additionally, thanks to tools such as polling data, politicians are amply aware of which terms engender a positive effect from a likely audience. One popular and common example that can quickly explain a person's political stance is whether they refer to a tax that occurs on a transfer of property following an owner's death as an “estate tax” or a “death tax”. While both terms refer to exactly the same legislation, the scarier term “death tax” is preferred by opponents of the law, while the gentler “estate tax” is used by proponents.
In cases such as the “estate/death tax” distinction without a difference, both opponents may be guilty of both a logical fallacy and a manipulative political mood. By emphasizing the importance of the distinction, using scary or softened terms, the audience may be distracted from the substance of an actual debate. By arguing ferociously over the irrelevant distinction, it may even seem as if opponents are trying to draw attention to the political theater rather than the substantive questions at the heart of the matter.
Advertising may also use the principles of distinction without a difference to market products. Sometimes, by doing something as simple as changing the color of a headache medicine from red to blue, a marketing campaign can claim the product is new, improved, and better than before. In fact, unless the color plays an important part in whether the medicine works or not, the change has created a distinction, but not a substantive difference that impacts an outcome.