Everything happens to everybody sooner or later if there is time enough.
— George Bernard Shaw, Back to Methuselah, pt. V
You’ve read the question, you’ve written your thesis statement, and now you have to support it. If you have problems coming up with ideas to support your statement, though, it may be that your argument is too general. Generalizations are not always bad, and there are cases where you really want to be able to say something about a whole class of things categorically. A claim that all prime numbers are all odd is properly tested and refuted by the single available example. In most cases based on practical daily experience, however, a broad, sweeping statement is almost impossible to support fully, and you may need to rewrite it. Always you need to keep your eye on the scope of what you’re setting out to do. Sometimes you just don’t need broad generalizations. If you don’t need them, they’re probably too expensive (in terms of argumentation and your time and effort in preparing that argumentation) to support.
main points for this unit
Here are some rules for writing a thesis statement that is clear and specific, rather than too general:
Not good: The habitat of the spotted owl has been destroyed. This can be easily refuted if you find even one spotted owl in the wild—because wherever it lives is an existing habitat.
Better: In the Pacific Northwest, the habitat of the spotted owl has been reduced. This is much more defensible, since you can probably show clear and positive evidence of habitat reduction. The question remains whether the reduction is significant in terms of species survival.
Not good: The Roman Empire persecuted Christians. It’s true; at some points in its history, it did. The problem here is that it didn’t always do so: under Constantine the Great, Christianity became the state religion.
Better: From the era of Nero to the reign of Diocletian, Christians were intermittently persecuted by the state. Now you just have to cite which emperors and give examples of how they were persecuted.
Not good: By law, houses must have plumbing and concrete foundations. This is generally true in the United States, under the Uniform Building Code; it’s not true worldwide, and it doesn’t apply to dog-houses or bird-houses. These things might or might not be relevant to your discussion: if there’s any reason to suspect that there’s a doubt about what you’re discussing, though, make your terms explicit.
Better: In the United States, the Uniform Building Code requires concrete foundations and a certain standard of plumbing for all single-family dwellings.
Once you have written your thesis statement — or the topic sentence of a supporting paragraph — you need to examine it for completeness. Let’s go back to our “better” statement about the spotted owl:
In the Pacific Northwest, the habitat of the spotted owl has been reduced.
First, notice that “reduced”, while it doesn’t imply total destruction and therefore is more defensible than our first generalization, leaves open the questions: reduced by how much? and does this amount matter to the owl? One tree down would be a reduction. But does it matter? Therefore, we need to add a limiting adverb or adjective—in this case, an adverb which gives us a term to discuss:
In the Pacific Northwest, the habitat of the spotted owl has been significantly reduced.
Admittedly, the claim here is open to validation, and probably somewhat subjective — but at least you are asserting for yourself that the reduction is in fact significant, rather than merely measurable.
In most situations, though, a reader — especially an unsympathetic one, or one who is yet to be persuaded of your position — wants to know what “significant” really looks like. Figure out your answer to that question and write it down, and fold it into your essay at some point. One might reasonably say that a significant reduction is the smallest amount that will materially affect the chances of the owl’s survival. Once this threshhold is reached or crossed, the owl is in danger of extinction. The threshhold for significant reduction could be as little as 1% or as much as 99%, depending on precisely how the owl lives, and you probably need some field studies correlating habitat destruction with reductions in owl population to determine what that threshhold is; you may well require further studies to determine whether that threshhold has been met. Without such information, you can’t honestly make the claim that you know whether the habitat has reduced enough to threaten the survival of the owl.
Once you write your thesis statement, you need to start asking yourself questions about the implications of the statement. For the essay topic:
Compare the civilizations of ancient Mesopotamia and Egypt. How do you account for the similarities and differences?
...your initial thesis statement might be something like:
Mesopotamian and Egyptian civilizations were different.
Okay; this takes a stand, because you could have claimed that they were the same. But there are two things wrong with it: we don’t have a clue as to how they were different, and probably any two civilizations (just by the fact that they weren’t the same one) might be presumed to be different. Strive for greater precision, and also consider what ways they might have been similar. Try again:
Mesopotamian and Egyptian civilizations shared many similarities and differences.
This, while allowing us to work with both similiarities and differences, still is pretty vague; what were the similarities and differences? How did they arise? What did they affect? After some further reflection, we come up with a possible thesis:
Ancient Mesopotamia and Egypt were both urban-led, agriculturally-based civilizations centered on rivers, but differences in climate and defensibility led each civilization to develop unique religious views and govermental institutions.
Now we have something that makes a specific claim and also something we can defend and elaborate: we can discuss the cities, the agriculture, and the rivers as the common features, and show the differences in religion and government as the result of differences in climate and the success or failure of invasions from outside tribes.
Once you have limited your thesis statement to something that you can easily support, you will need to provide your reader with concrete examples — historical events, citations from documents, references to examples in a work of literature, or the results of experiments or surveys. You cannot, however, just list the examples; you must also tie each one to your main point or to some part of it.
In the case of the owl essay, you would need to determine what the owl’s habitat is (old growth forest), how much has been destroyed and over what period of time (say during the last 40 years, by looking at Forest Service records and private holdings), and then determine whether the owl population has been decreased in that time (from bird studies or surveys). Each of these points explains some part of the thesis statement, but you will need to draw the connection for your reader. Often you can do this by using the same terminology:
...The spotted owl’s habitat lies in old growth forests of Oregon and Washington...
but sometimes you will have to be more explicit:
“Significantly reduced” in this case means by an amount large enough to threaten the owl’s ability to survive and reproduce.
Summarizing is the act of making a generalized statement after you have provided the detailed information. The summary points out the factors that are common to the different examples, or suggests a cause-and-effect relationship. The summary, however, is subject to the same restrictions as the examples are. You still cannot go out on a limb beyond what is warranted by your examples and supporting information. After listing six successive Roman emperors who issued orders for the suppression of Christianity, you can say that during the reigns of the emperors from the first to last on your list, Christians were persecuted. You cannot claim that Christians were persecuted throughout Imperial Rome for all of its existence. After showing that a 30% reduction in old-growth forest resulted in an 80% reduction in owl population, and that the remaining breeding pairs in a particular area are too few to sustain a permanent population, you can claim that the owl is endangered in that area. You cannot claim that the owl is threatened throughout its territory from this one example.
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