This is not an exhaustive list of bad thesis statements, but here're five kinds of problems I've seen most often. Notice that the last two, #4 and #5, are not necessarily incorrect or illegitimate thesis statements, but, rather, inappropriate for the purposes of this course. They may be useful forms for papers on different topics in other courses.
1. The non-thesis thesis.
A thesis takes a position on an issue. It is different from a topic sentence in that a thesis statement is not neutral. It announces, in addition to the topic, the argument you want to make or the point you want to prove. This is your own opinion that you intend to back up. This is your reason and motivation for writing.
Bad Thesis 1: In his article Stanley Fish shows that we don't really have the right to free speech.
Bad Thesis 2: This paper will consider the advantages and disadvantages of certain restrictions on free speech.
Better Thesis 1: Stanley Fish's argument that free speech exists more as a political prize than as a legal reality ignores the fact that even as a political prize it still serves the social end of creating a general cultural atmosphere of tolerance that may ultimately promote free speech in our nation just as effectively as any binding law.
Better Thesis 2: Even though there may be considerable advantages to restricting hate speech, the possibility of chilling open dialogue on crucial racial issues is too great and too high a price to pay.
2. The overly broad thesis.
A thesis should be as specific as possible, and it should be tailored to reflect the scope of the paper. It is not possible, for instance, to write about the history of English literature in a 5 page paper. In addition to choosing simply a smaller topic, strategies to narrow a thesis include specifying a method or perspective or delineating certain limits.
Bad Thesis 1: There should be no restrictions on the 1st amendment.
Bad Thesis 2: The government has the right to limit free speech.
Better Thesis 1: There should be no restrictions on the 1st amendment if those restrictions are intended merely to protect individuals from unspecified or otherwise unquantifiable or unverifiable "emotional distress."
Better Thesis 2: The government has the right to limit free speech in cases of overtly racist or sexist language because our failure to address such abuses would effectively suggest that our society condones such ignorant and hateful views.
3. The incontestable thesis.
A thesis must be arguable. And in order for it to be arguable, it must present a view that someone might reasonably contest. Sometimes a thesis ultimately says, "we should be good," or "bad things are bad." Such thesis statements are tautological or so universally accepted that there is no need to prove the point.
Bad Thesis 1: Although we have the right to say what we want, we should avoid hurting other people's feelings.
Bad Thesis 2: There are always alternatives to using racist speech.
Better Thesis 1: If we can accept that emotional injuries can be just as painful as physical ones we should limit speech that may hurt people's feelings in ways similar to the way we limit speech that may lead directly to bodily harm.
Better Thesis 2: The "fighting words" exception to free speech is not legitimate because it wrongly considers speech as an action.
4. The "list essay" thesis.
A good argumentative thesis provides not only a position on an issue, but also suggests the structure of the paper. The thesis should allow the reader to imagine and anticipate the flow of the paper, in which a sequence of points logically prove the essay's main assertion. A list essay provides no such structure, so that different points and paragraphs appear arbitrary with no logical connection to one another.
Bad Thesis 1: There are many reasons we need to limit hate speech.
Bad Thesis 2: None...