The appeal to novelty (also called argumentum ad novitatem) is a fallacy in which someone prematurely claims that an idea or proposal is correct or superior, exclusively because it is new and modern. In a controversy between status quo and new inventions, an appeal to novelty argument isn't in itself a valid argument. The fallacy may take two forms: overestimating the new and modern, prematurely and without investigation assuming it to be best-case, or underestimating status quo, prematurely and without investigation assuming it to be worst-case.
Investigation may prove these claims to be true, but it is a fallacy to prematurely conclude this only from the general claim that all novelty is good.
The opposite of an appeal to novelty is an appeal to tradition, in which one argues that the "old ways" are always superior to new ideas.
Appeals to novelty are often successful in a modern world where everyone is eager to be on the "cutting edge" of technology. The so-called "Dot-com bust" of the early 2000s could easily be interpreted as a sign of the dangers of naïvely embracing new ideas without first viewing them with a critical eye. Also, advertisers frequently extoll the newness of their products as a reason to buy. Conversely, this is satirised as bleeding edge technology by skeptics (this may itself be an example of the appeal to tradition fallacy).
The appeal to novelty is based on the reasoning that in general people will tend to try to improve the outputs resulting from their efforts. Thus, for example, a company producing a product might be assumed to know about existing flaws and to be seeking to correct them in a future revision. This line of reasoning is obviously flawed for many reasons, most notably that: it ignores motive (a new product may be released that is functionally identical to previous products but with new packaging); it ignores cyclicality (the fashion industry continually rediscovers old styles and markets them as the next new thing); and it ignores population dynamics (the previous product may have been created by an expert who has since been replaced by a neophyte).
In some cases, there may exist one or more unnamed - but still universally acknowledged - correlations between novelty and positive traits. For example, newer technology has a tendency to be more complex and advanced than older. A correlation may for example exist between newness of a virus definition file and the security of a computer, or between the newness of a computer and its speed and performance. In these precise cases, something is more probable to be superior whenever it is new and modern, though not exclusively because they are new and modern. Thus, what may seem like Appeal to novelty isn't a fallacy in every case. It is only a fallacy if this correlation is disputed or if no such correlation has been examined.
In aesthetics, for example in some arts and musics, novelty - though not all forms of novelty - is used as a criterion for acclaim. This may look like the fallacy, but in some circles there may be an unnamed consensus that people eventually grow tired of what they're used to. In these cases, the aforementioned criterion and justification isn't based exclusively on Appeal to novelty, and thus is no fallacy.