Logical fallacies are often used, intentionally or otherwise, to push people toward beliefs that are based on something other than solid logical reasoning. When writing formal arguments, one should try to avoid writing sentences with fallacy; as a reader, one should work to be aware of such sentences so as to ensure that one judges arguments based only on solid reason. To identify sentences with fallacy, one should first study the different types of logical fallacies. Next, one should work through every sentence in an argument. Examining each sentence for logical consistency should allow one to tell if a given sentence — and by extension the argument to which it contributes — contains a logical fallacy.
It can be difficult to identify sentences with fallacy if one is not familiar with the different types of logical fallacy. Familiarizing oneself with common types of logical fallacies makes identifying fallacious arguments much easier, as many common faulty arguments have easily recognizable formats. Common types of fallacies include attacking a person's character rather than his argument, suggesting that not knowing whether or not something is untrue means that it is true, and arguing that something is true because an authoritative figure says it is. Familiarizing oneself with these and many of the other common forms of fallacy is a good way to learn to identify sentences with fallacy.
When reading over any argument, particularly if it will influence a future opinion or decision, it is important to search for sentences with fallacy. Armed with a working knowledge of the different forms of fallacy, one should examine each of the arguments used to support a given claim. If an argument contains one of the common fallacies, it likely will not actually provide support for the claim. Even if one does not immediately recognize a common fallacy, it is still important to ask exactly how a statement provides logical support for a claim. If one cannot identify a clear and logical connection, it is likely that fallacy exists.
It is easy to inadvertently use sentences with fallacy in one's writing. As such, a person should check his own writing for sentences with fallacy even more rigorously than he checks the writings of others. One should examine each statement and ask if that statement is based on logical premises or if it is, instead, based on a preconception that does not actually have a basis in logic. One should also make sure that each statement stands on its own and is not dependent on an emotional appeal or an appeal to some higher authority, such as a professor.