Using Literature

How many sources should a philosophy paper use? How do you cite these works? How do you present other philosophers’ ideas and arguments in your paper? These are very common questions which students face. Let’s look at the ways you should and should not use literature in your essays.


How many sources?

Some teachers and subjects may specify a minimum number of references per paper. In philosophy, this is unusual behaviour. We don’t normally have a guideline number because different philosophy papers need different levels of engagement with literature.

A good guideline for philosophical writing is:

Think more, read less.

In other words, a good philosophy paper showcases more thinking than it does reading. This is what markers mean when they talk about papers that show independence or originality: evidence of thought. Unlike other disciplines, the vast majority of philosophers don’t perform experiments, collect data or do archival research. Our work consists of turning over problems and thinking in great detail about them. You can try to shortcut this process by reading – by harnessing the thinking other philosophers have done. But you can’t wholly substitute other philosophers’ thoughts for your own and still produce an exceptional paper.

But you need a starting point for thinking. What are you going to think about? This is the first stage in accumulating sources: finding and understanding your subject-matter. If you’re writing a paper for a course, this starting point is probably given by your essay question and by the sources which form the core readings for the course. Start with those to identify the points you want to discuss in your paper. You will need to cite at least some of these sources when you outline your focus in your paper. You only need to cite those which you end up drawing upon in writing your paper.

NB: Some teachers may be unhappy if you don’t reference all of the required readings on a topic which you’re writing on. Check with your teacher about their expectations. If a paper is genuinely not at all relevant to your essay, you might consider using a caveat to include it. (See our guide to Structure for ideas about caveats).

This is the point where you need to engage the brain. What do you think about this topic? That will form the starting point for your thesis. What is your argument? The Constructing an Argument guide can help you to formulate that. Now, you need to anticipate the likely criticisms of your position and your argument. If you can do this for yourself, then that’s fine. But usually it’s hard to think why others will disagree with you. This is another stage where reading is important. Try to identify sources which specifically criticise the argument you’re making. Cite these when you begin to defend your argument from criticism. You might need some help in refuting those arguments – again, look for authors who have defended that position, and be very careful to ensure you cite them. It’s never OK to take their arguments without attribution, even if you rephrase their ideas in your own words.

Sometimes, you will be focusing very specifically on a particular philosopher’s work or a point they have made. Good essays can be written which focus extremely closely on a single text, dissecting that one author’s ideas. Obviously, you will need to cite that source. In this case, a single source might actually suffice. But, given that you’re focusing on that one author, you are taking a risk – your essay’s success depends on correctly understanding the author’s work. It’s a good idea, in that case, to corroborate your understanding of the text by comparing your reading of the text with other works by the same author, or secondary works by others who comment on the text you’re analysing. Citing those in your paper will help you to substantiate and justify your interpretation.

So – no clear answer, then. There is no right or wrong number of sources. You should be citing everything you need in order to put forward your interpretation of the author(s) you discuss, and to defend your argument successfully.


How do I avoid plagiarism?

Plagiarism is an extremely serious academic offence. If you represent another person’s work as your own – either on purpose or accidentally – that is plagiarism.

Given the seriousness of the accusation, you should head off any possibility of plagiarising. Usually, if you have to ask “Should I be referencing here?”, the answer is yes. Adding the reference doesn’t damage your paper, but failing to do so could. If in doubt, add the reference.

Accidental plagiarism is trickier to prevent. Accidental plagiarism happens when someone uses a phrase or idea they’ve taken from someone else without attribution and without realising that the idea or phrase is not their own. This usually results from certain note-taking practices. Some people like to take notes by copying phrases from readings or lecture slides into their own notes. That’s not necessarily bad. But if you copy down a phrase into your notes, and then forget that the phrase came from someone else, you could end up copying that over into your essay, especially if there’s a considerable time between the note-taking and the essay-writing.

The best way to avoid this is to write with an empty desk. When you set out to write, put your notes and readings aside. This has a number of beneficial effects. It prevents accidental plagiarism. It also encourages you to phrase things in a new and original way, and to focus only on the key points without feeling the unhelpful impulse to try to include everything you’ve read or heard about. Finally, it will help you to identify your focus in the essay – the things that stand out to you well enough to stick in your mind when writing without your notes are probably the topics you find most interesting.


How do I reference?

Referencing is very simple. It used to be a terribly complex matter which involved libraries, card catalogues and physical copies of journals. But now, it’s a much, much easier process. This is to your advantage. Many of your markers remember proper referencing being more challenging, and still see it as an indicator of effort, when in fact it’s very straightforward. Never throw away that advantage by rushing or omitting your referencing. Get it right, and you’ll get a wave of goodwill from your marker or reviewer.

First, how do you find the relevant bibliographic material? Whether you’re citing a book or an article, Google Scholar is a very useful resource. Search for the text on Google Scholar, and then hit the “Cite” button below the entry (this button now looks like a stylized quotation mark: ” ). A pop-up will appear with all of the bibliographic details Google has on file for that text, already pre-formatted in 5 of the main bibliographic formats (APA, MLA, Chicago, Vancouver and Harvard). You can also download this data directly into referencing management software such as EndNote, Bibtex, Refman or Refworks too. Often, Google Scholar has complete information. Sometimes it’s incomplete. If it doesn’t have everything you need, you can usually follow up the links Google Scholar provides to fill in the rest of the info.

Which format do you need to use? There are many out there. Many journals have their own style. Check with your teacher or course guide which style is preferred, and use whatever they tell you to use. Increasingly, teachers don’t mind what style you use as long as you’re consistent. So pick one that’s accepted and familiar, and stick to it.

A complete reference contains a range of data. A full journal article citation in the APA format looks a little like this:

Gettier, E. L. (1963). Is justified true belief knowledge? Analysis, 23(6), 121-123.

Here you have the author’s surname, followed by their initials, then the date of publication, title of the paper, the journal’s name (italicized), then the volume number (23) and issue number (6), and finally the pages. This is a complete reference. Where you have multiple authors, some styles call for you to list them all, but others only need all of the authors up to a maximum of three, e.g.:

Djulbegovic, B., Guyatt, G. H., & Ashcroft, R. E. (2009). Epistemologic inquiries in evidence-based medicine. Cancer Control, 16(2), 158-168.

If you have more than three authors, you can use just the first author and append “et al.” (if your chosen style allows) to indicate that there are multiple others, e.g.:

Davidoff, F., et al. (1995). Evidence based medicine. British Medical Journal, 310(6987), 1085.

When you’re referencing a book or a chapter from an edited collection, the data needed is a little different. Books are quite straightforward:

Douglas, H. (2009). Science, policy, and the value-free ideal. Pittsburgh, Pennsylvania: University of Pittsburgh Press.

Along with the usual author’s name, date and title (italicized), we now have the place of publication and publisher. This data can be a little trickier to come by, particularly the place of publication, and as a result many people are now happy with just the publisher’s name. Many books have been published in numerous locations by different publishers across their lifetime, especially if multiple editions have been published. If a book clearly states its edition number, include that in your reference as the book may have been substantially revised, and pagination is likely to be very different.

When citing a chapter from a book, we merge elements of the article and book style. When done properly, it looks like this in APA format:

Rachels, J. (1975). Active and passive euthanasia, in N. S. Jecker, A. R. Jonsen & R. A. Pearlman (Eds.) Bioethics: An Introduction to the History, Methods, and Practice, 77-82, Sudbury, Massachusetts: Jones & Bartlett.

Here we referenced the chapter title, but then made it clear that this was part of an edited book with three editors. (Ed.) denotes an editor, while (Eds.) is used to denote multiple editors. Then we give the full reference for that book, adding in the page numbers of the chapter itself.

The final common task for referencing is a web-page. This can be particularly tricky as the data is not always readily available. A key rule is that it is never acceptable to merely provide the URL as a citation. 

When citing a website, try to provide a similar level of information to an article or book – the authorship, date of (most recent) publication if known (you might find this by checking the copyright text often located at the foot of the page), and title. If you know the precise date of publication (for instance with a blog post), you can provide that too. You should provide a URL, preferably a “permalink” – which is a URL which should not be subject to change or relocation. Finally, you must provide an access date, which tells your reader when you consulted the web-page. Because pages can be subject to regular and substantial changes, providing this means that if the site is heavily revised, your reader can use tools like Wayback Machine to consult a historical version of the page. A good citation of a website in APA formatting looks like:

Blunt, C. J. & Runhardt, R. W. (2018) Using Literature, Retrieved from: (24/01/18).

Putting together this info from our website takes a little bit of digging but not too much. The “about the authors” page provided the names of the likely authors, which isn’t contradicted anywhere on this page. The date of publication was taken from the copyright message at the foot of the site, and the URL was copied over, along with today’s date. Some of these details might have changed by the time you read this, and we may have revised this article. If so, you could (try to) look back to how the site looked in January 2018 to see what I was reading and citing at that time.

You might have to cite other things – newspaper articles, videos, databases, encyclopedia, magazines, etc. If you have an unusual citation, look for a style guide in your chosen referencing style. Sites like easybib may be able to help.

There are two components to referencing: the in-text reference and the full citation. The in-text reference tells your reader, at the point you discuss an idea or use a phrase, where that idea or phrase came from. This is often a brief note. There are three main styles of in-text referencing: footnotes, endnotes and author-date.

footnote style involves putting either the full citation or an abbreviated form of the citation in a footnote. For instance:

Here, you see the author referencing Popper by using the full citation in a footnote. If the author had quoted from Popper, they’d need to add a page number to this reference. One of the advantages of this style is that the text itself remains relatively uncluttered. Another is that by putting the full citation in the footnotes, you don’t really need a separate bibliography at the end. But there are some disadvantages. First, if you’re writing to a strict word limit, and footnotes count towards those limits, then this style will use a lot more of your words on referencing than an author-date or endnote format. Second, if you reference quite a lot of papers, you can end up with a big unsightly list of references at the foot of each page. However, this is a common and accepted form of referencing.

The author-date style embeds in-text citations within the text, and then lists the full citations in a bibliography at the end. In this style, you include two (or sometimes three) pieces of information within the text – the author(s) name(s), the date of publication, and (if necessary) the page numbers. For example:

Here, the author references both Popper and Wisdom using the author-date style. As you see, there are two ways this can be done. In the first case, Popper is not explicitly mentioned within the sentence, so both author and date are used: “(Popper, 1963)”. In the latter case, Wisdom is mentioned by name so it’s not necessary to include the name again: “John Wisdom (1953)”. In either case, if the author had quoted from Wisdom or Popper, they’d need to include a page number. For example:

So, “theory does not stem from observation, it stems from reasoning and speculation.” (Popper, 1963, p.25)


As Popper claims, “theory does not stem from observation, it stems from reasoning and speculation.” (1963, p.25)

If the quotation spans across multiple pages, use: pp.25-6 or pp.29-30. Don’t use “pg”, “ps” or “pgs” to indicate page numbering: ‘p’ and ‘pp’ are now standard. In some referencing systems, you don’t need the ‘p’ or ‘pp’ at all and can simply indicate using a comma or colon, e.g.: “(Popper, 1963, 25)” or “(Popper, 1963: 25)”. Use whatever format your teacher or journal of choice requires. If they don’t have a preference, use whatever you prefer. You can also cite footnotes and figures in this way. ‘n.’ is commonly used for a footnote, and ‘fig.’ for a figure. When citing a webpage, it is often not possible to provide a page number. If you can narrow down where on the page the text appears in some way, try to provide that (e.g. ‘Section 4’). But if not, you’re going to have to leave it out. You might get flack for that from a marker or reviewer. That’s too bad. Always try to find a paginated version of an article if you can, even when viewing it online. Most journals allow you to open a pdf copy of an article which will most likely have page numbers included.

Author-date has several advantages – the text is not too cluttered, it uses relatively few words, and only needs the full citation at the end in a separate bibliography. It also means that the reader can see immediately which scholars are being cited without having to scroll to the end or to the foot of the page. It is a very common approach which is, in philosophy, usually the default style.

The endnote style (not to be confused with EndNote, a piece of referencing management software) uses numbered references in the text, and then gives the full citation at the end. For instance:

Here, the author references Popper and two papers by Lakatos. The advantages here are that the text stays uncluttered, and that a large number of papers could be referenced at once without using lots of space in the text or in the footnotes. If referencing three of more papers, one could condense that as: [1-3] or [7-11]. As a result, this style can be very helpful in scientific publications where multiple data sources are referenced at a time. This is generally less advantageous in philosophy. A disadvantage is that the reader has to go to the end of the paper to work out who is being cited. If page numbers are required, these can also be included, e.g.:

So, “theory does not stem from observation, it stems from reasoning and speculation.” [1:25]


Should I quote?

Usually, no. One of the distinctive features of philosophical writing which differs from many other disciplines is that it is considered unnecessary to provide extensive quotations. There are many reasons for this.

First of all, quoting doesn’t demonstrate your understanding. You can quote a complex passage, but unless you explain it in your own words, a marker has no evidence that you understand. Quoting and then explaining in your own words wastes precious space by repeating the idea. So just skip the quote and present it yourself, along with a reference.

Second, consistent use of terminology is really important. Philosophers have often spent considerable energy defining and distinguishing between similar terms. Some philosophers use different terms to others, and these might have slightly (but importantly) different meanings. You need to use the same terms throughout your paper, otherwise you’ll get sidetracked and waste lots of space by defining lots of terms (or worse, operate with ill-defined terminology). When you quote, you’re restricted to using the terminology of that source, and you need to define their terms if you haven’t already.

So when is it appropriate to quote? There are a couple of situations.

  1. Very short phrases – quote brief phrases and terms which are helpful to make your point clear. For instance: ‘Popper calls the the “principle of empiricism” (1963, p.22)’
  2. When you will discuss the specific wording used in detail. When a philosopher puts forward a precise definition or conceptual analysis which you’re going to analyse in detail, quoting it may be necessary in order to make your discussion clear and accurate. Here, the fact that you go on to discuss it at length makes it clear that you understand the material.
  3. When people might not believe that the author really said what you say they said. If you see an author making a very controversial claim, contradicting something they said elsewhere, or endorsing a view that they might be expected to reject, and you want to discuss that, then you might have to quote them in order to prove that they really did say it. If you read Kant saying “Utilitarianism is the correct moral theory”, then you better provide the quotation and reference, because otherwise nobody will believe you!

What kinds of quotation should you avoid? Any long quotations which you could equally have put in your own words. Any quotations which you don’t go on to discuss. Most importantly, any pretentious quotes which don’t have much in the way of meaning. No one is going to be impressed by that obscure quotation from a classic novel or a piece of poetry, and it will likely make your point less clear. Translate any foreign language quotations.

Whenever you quote, you must provide a page number. If the source you’re quoting has pages (i.e. it’s not a website or similar source), you need to give the page number with your reference. This is so that your reader can check that your quote (a) really exists, and (b) hasn’t been taken out of context. Which leads to a second rule:

Never quote someone out of context. Suppose Kant had really said “Utilitarianism is the correct moral theory”, but the full context was: “Some people think that Utilitarianism is the correct moral theory. However, they are mistaken.” Clearly, the quote is then misleading. Kant doesn’t actually think Utilitarianism is right. This is an illegitimate use of quotation, and will be frowned upon and used as evidence of intellectual dishonesty. Don’t be like those movie posters that say “Eddie Murphy is comic genius” when the actual review says: “Eddie Murphy is comic genius, so why does he keep churning out these terrible movies?”