You may have heard that it’s not necessary to cite a source if the information it provides is “common knowledge.” In theory, this guideline is valid. (See principle #4 in “When to Cite Sources.”) In high school, the guideline is often further simplified: if you can find the information in The World Book Encyclopedia, then it’s “common knowledge.”
However, when you’re doing sophisticated original work at the college level, perhaps grappling with theories and concepts at the cutting edge of human knowledge, things are seldom so simple. This guideline can often lead to misunderstanding and cases of potential plagiarism. The concept of “common knowledge” can never be an objective criterion for the obvious reason that what is commonly known will vary radically in different places and times. Human understanding is constantly changing, as the tools by which we can observe and comprehend the universe develop and as the beliefs that shape that understanding evolve. In medieval times, for example, it was an incontrovertible fact that the Earth was at the center of the universe. What a Chinese acupuncturist knows about human anatomy and health is remarkably different from what an American-trained surgeon knows. And what Princeton concentrators in molecular biology know today about the human genome would bewilder and astound Princeton biology students of only two generations ago. To complicate matters, each discipline has its own evolving definitions, and its own tests, for what constitutes a “fact.” And even within disciplines, experts sometimes disagree.
The bottom line is that you may be unable to make informed decisions concerning what is and is not “common knowledge.” That will be less true as you get to know a topic in depth, as you will for your senior thesis. But, especially in fields with which you’re less familiar, you must exercise caution. The belief that an idea or fact may be “common knowledge” is no reason not to cite your source. It’s certainly not a defense against the charge of plagiarism, although many students offer that excuse during the disciplinary process. Keeping in mind that your professor is the primary audience for your work, you should ask your professor for guidance if you’re uncertain. If you don’t have that opportunity, fall back on the fundamental rule: when in doubt, cite. It’s too risky to make assumptions about what’s expected or permissible.
The new era of electronic media and the Internet has made this issue even more complex and uncertain. The depersonalized nature of electronic information can devalue the sense of intellectual ownership: the information seems to belong to nobody and to everybody. The protocols for borrowing, reusing, and modifying information on the web are less well-defined than they are in more traditional scholarly research and far less diligently observed. Indeed, much of the ethic of the Internet, which emerged from the computer culture of collaborative work and shareware, is in tension with the values and practices of traditional scholarship, especially in the humanities and social sciences. With the web’s countless sites offering text and images for the taking, and with commercial sites offering free educational versions of their software, the lines between public and private ownership of intellectual property have become blurry. Many of us have been tempted to download and save a particularly appealing image from the web, never quite knowing whether or not the image is copyright-protected.
Because you can’t readily trace the sources for the information found on the web, you may feel less obligated to acknowledge electronic sources. However, at Princeton, you are expected to observe the regulations for academic citation of all sources, print or electronic. The same rules apply to copying verbatim text or images, paraphrasing, and summarizing material from the web. And given that information and data available on the web may not receive the same stringent review as more traditional scholarly sources, you must be extra careful about evaluating and acknowledging your web sources for such information.
Finally, all of us are aware of websites that offer academic papers for sale or that offer to do the research and writing for you. For Princeton students, such services are far less tempting because the academic quality of such papers tends to fall short of any acceptable Princeton standard. Nevertheless, you should know that any use of such services by a student is considered not just plagiarism but academic fraud, and is subject to the most severe penalties.