I've read this and this. I know that the underlying question has been answered, my problem is of a different nature: I'm currently writing my master's thesis in CS and my professor thinks that the apostrophe possessive is only applicable to people. He claims to have spoken to a linguist from Cambridge who confirmed his opinion. Neither my professor nor I am a native speaker and the thesis is being written in Germany. Now, I know that he won't care if I just send him a couple of links to the answers here.

So my question is: How do I convince my professor? Are there any "more scientific™" sources that I can point to?

Examples of phrases:

  • If each plant's humidity is displayed publicly [...]
  • [...] shows an overview of the node's structure.
  • Due to an issue in the network stack's IPv6 subsystem [...]
  • 5
    This is a rule for elementary learners of English. It is not a grammatical rule, it's a guide for basic English learners natural English until they're able to judge the felicity of the genitive NP on their own. Commented Sep 14, 2015 at 12:55
  • 3
    Good idea! @Mari-LouA - Found an example here at the beginning.
    – fresskoma
    Commented Sep 14, 2015 at 15:38
  • 4
    You've nailed him! But I'm not sure if this is a good thing, you certainly don't want to embarrass or belittle him, on the other hand you have Charles Darwin and English native speakers on your side. I don't know what kind of rapport you have with your professor, nor his precise role in your thesis. I am not an academic, so perhaps you could post a related question in SE. Academia, asking what should be your next move. Unless someone here can also confirm T.E.D's answer.
    – Mari-Lou A
    Commented Sep 14, 2015 at 16:24
  • 5
    Your professor is lying about his Cambridge friend. Not a good sign for a high-ranking educator. Commented Sep 14, 2015 at 18:17
  • 20
    Whenever I have to argue against a friend in Cambridge, I defer to my friend from Oxford: oxforddictionaries.com/words/apostrophe
    – ps2goat
    Commented Sep 14, 2015 at 20:33

10 Answers 10


As few people are addressing the '"more scientific™" sources' bit of the question, it should be pointed out that there are a number of English style guides out there, practically all of which should cover the topic of forming possessives with apostrophe-s (as it's a frequent issue even with native speakers).

You should be able to find copies of at least one of the major ones in any decent University library. (At least at any decent University with English classes.)

  • The Elements of Style by Strunk and White is the "gold standard" for many Americans, although there are many who disagree with many of the details.
  • The Chicago Manual of Style is a well-used standard for (American) University usage. - The online version is unapologetic and direct on this topic: "The possessive of most singular nouns is formed by adding an apostrophe and an s", although it does go into more details.
  • Fowler's modern English usage by Henry Fowler is also a well-regarded standard, particularly for British users.
  • The Cambridge Guide to English Usage by Pam Peters has the benefit of the "authority" of Cambridge. Oxford, of course, has their own: The New Oxford Style Manual, though the title has varied with edition.

If physical copies aren't something you're interested in, a number of organizations (particularly journalism houses) have their house style guides online.

  • For example, the Economist makes no mention of the conjectured rule in its advice.
  • The Guardian gives additional examples, and also completely omits the purported rule.
  • Others can likely be found by searching, and other major organizations (like the Associate Press and the New York Times) have theirs as printed books.

Many dictionaries also have usage notes in them. (In particular, I'll point out the comment from @ps2goat mentioning Oxford Dictionaries's online page.)

Ultimately, though, it's exceedingly difficult to prove a negative. Even confronted with evidence that a large number of style guides and usage manuals for English have nothing approaching the purported rule, your professor might not be convinced that he is mistaken. If that is the case, your best choice is probably to reword things to avoid the issue.

  • 2
    Even if the style manuals don't have this rule, I bet they are using the apostrophe at some point. A few examples from The Cambridge Guide to English should make a convincing argument.
    – Davidmh
    Commented Sep 15, 2015 at 11:29

The strongest endorsement that I could find from a UK English source in favor of using 's after singular nouns of any kind to indicate possession is this brief treatment from The Oxford Guide to Style (Oxford University Press, 2002):

5.2.1 Possession

Use 's after singular nouns and indefinite pronouns that do not end in s:

[Examples:] the boy's job, the BBC's policy, nobody's fault, the court's decision, the bee's knees, one's car, Oxford's bells, Mary's garden, a week's time, Yasgur's farm

As the examples accompanying this guideline rather obliquely suggest, the situations in which re-forming an expression from "X's Y" to "the Y of X" has the most deleterious consequences are the ones involving idioms: "the knees of the bee" and "the meow of the cat" sound ridiculous—and indeed foreign—when rendered thus. But so does "the time of a week" (or to a lesser extent, "the span of a week" or "the duration of a week") in place of "a week's time," or "the thought of a moment" for "a moment's thought."

Another treatment, with fewer nonhuman examples of the 's treatment in action is from the "English Grammar Today" section of Cambridge Dictionaries Online:

Possessive 's

We use apostrophe s (’s), also called possessive ’s, as a determiner to show that something belongs to someone or something:

Is that Olivia’s bag?

Britain’s coastline is very beautiful.

We can also use it in complex noun phrases:

Greg is her youngest daughter’s husband.

We can use two possessive ’s constructions in the same noun phrase:

We went to Jake’s father’s funeral.

We also use possessive ’s to talk about time and duration:

Is that yesterday’s paper?

I’ve only had one week’s holiday so far this year.

A bit later in the same discussion, the Cambridge guide points out a feature of English in an accurate but potentially misleading way:

We don’t usually use the possessive ’s with things:

the door handle

Not: the door’s handle

the shop window

Not: the shop’s window

the kitchen table

Not: the kitchen’s table

But native English speakers who blithely say "the bee's knees" and "the cat's meow" wouldn't say "the door's handle" or "the kitchen's table" in any event, because the nonpossessive form is sufficient; for the same reason, they wouldn't be inclined to say "the handle of the door" in preference to "the door handle," and they certainly wouldn't say "the table of the kitchen" in preference to "the kitchen table."

However, the Cambridge Dictionary page doesn't stop there. Farther down the page it offers these guidelines:

’s or of or either?

There are some general rules about when to use ’s and when to use of but there are many cases where both are possible:

The film’s hero or The hero of the film

The car’s safety record or The safety record of the car

The report’s conclusion or The conclusion of the report

Sometimes when we first mention a noun, we use of, and later when we refer to it again, we use ’s:

The mountains of Pakistan are mostly in the north. At least one hundred of them are above 7,000 metres … Most of Pakistan’s mountains are in the spectacular Karakoram range.

When we don’t use ’s

We don’t use ’s when the noun is not a person, animal, country, organisation, etc., or when the noun phrase is very long:

The name of the ship was ‘Wonder Queen’. (preferred to The ship’s name was ‘Wonder Queen’.)

The house of the oldest woman in the village. (preferred to The oldest woman in the village’s house.)

When we don’t use of

When we are talking about things that belong to us, relationships and characteristics of people, animals, countries, categories, groups or organisations made up of people, we usually use ’s:

The men’s dressing room is on the left at the end of the corridor.

Not: The dressing room of the men

The cat’s paw was badly cut.

Not: The paw of the cat

This block of advice is exceedingly difficult to make sense of. In one section we read that "film's hero" and "car's record" and "report's conclusion" are all okay, despite their not being a person, animal, country, or organisation, and in the very next section we're informed that "We don’t use ’s when the noun is not a person, animal, country, organisation, etc., ..." Either the etc. at the end of that phrase is large enough to comprehend works of art, machinery, and publications (among other possibilities) or the guidelines aren't paying attention to one another.

Clearly, even Cambridge's online grammar guide doesn't endorse your professor's rule limiting the application of 's possessive forms to people. But it does muddy the water sufficiently that a determined professor might find some solace (if not vindication) there.

To me, the greatest harm that an endless series of "the Y of X" constructions does to a lengthy piece of writing, when used in place of a mixture of "the Y of X" and "X's Y" elements, is to make the writing sound needlessly wooden and rote. It's easy to underestimate the contribution that varied elements make to an essay—until you read one that uses the same restricted palette of constructions over and over.

The Oxford Guide to Style puts no restriction on what sorts of singular nouns can take 's to yield a possessive form. The Cambridge guidelines, though all over the place, at least indicate that significant areas of nonhuman things can be assigned 's possessives. I would be inclined to show both the Oxford treatment and the Cambridge treatment to the professor and ask him what he made of them. Even a shift from his current person-only rule to Cambridge's person, animal, country, organisation, etc.-only rule would give you some latitude in concluding that a plant, a node, and a network stack, for example, were all covered by the "etc." term of the latter rule.

  • 2
    I find this to be the best answer to the question in terms of questions and answers appropriate for this site, as opposed to Academia.SE. +1. Commented Sep 15, 2015 at 13:23
  • 1
    "The door handle" and "the kitchen table" may be interpreted as not possessive. That is, in these examples, "door" and "kitchen" are adjectives. What kind of table is it? It is a kitchen table. What kind of handle is it? It is a door handle. That use is, to some extent, cultural and/or idiomatic. However, in all English dialects of which I am aware, that is the correct use of such modifiers. Outside of such standardized cases, the possessive would be correct: the childrens' ball, the movie's hero, the professor's mistake, etc.
    – taz
    Commented Sep 15, 2015 at 15:36
  • 1
    @mattdm: Thanks for pointing out the error. After all these years, my fingers and my keyboard are still not good friends. (I continually hit the gap between keys and nothing registers—and I sometimes don't notice it.)
    – Sven Yargs
    Commented Sep 15, 2015 at 17:13

A piece of advice here from someone who did a CS Master's thesis himself:

You don't. You write it the way they want it written. Consider it like a house style guide. The rules in style guides aren't the only way to do proper English; just the way they do it there. Your goal here is to get a CS Master's, not a Booker Prize.

Look at it this way: Your advisor has a role to play too. They are supposed to provide you feedback. That means pointing out issues in your thesis. They have to do that, or they won't feel like they are doing their job. If all they are pointing out is debatable grammatical errors, that's a Good ThingTM. If you don't give them their niggly little errors, they will have no choice but to go looking for something more substantive to gig you on. That could cause you weeks of work, rather than a few seconds.

Perhaps a little pro-forma pushback on your part might be a good idea, to keep up appearances. But it sounds to me like you've already accomplished that.

  • 2
    I would tend to agree with the "You Don't" answer. If rephrasing a few lines is all you need to do to keep from mixing German and English then I'd say you have a ready-made solution. This may be one of the hardest learned lessons from your educational experience: Pick your battles.
    – Elliot
    Commented Sep 14, 2015 at 17:35
  • 2
    The resulting sentences should only be minimally awkward, or not awkward at all, to native English speakers if you just give in and rewrite your statements to avoid the 's's ( :D ) - the phrasing will wind up being close enough to normal that no one is likely to stumble over it.
    – Jason
    Commented Sep 14, 2015 at 19:56
  • 24
    This answer is very unfortunate. It's saying "do wrong, if you're told to do wrong by someone to whom you have to kow-tow." if you put this ridiculous, idiotic error in your paper, I say that is you who will look like a fool for the rest of your life, not the professor.
    – Fattie
    Commented Sep 14, 2015 at 20:30
  • 5
    I have to agree with @Joe here. Saxon vs. Romance genitives may not be a big deal, and the worst you’ll come out looking like is someone who’s not a native speaker of English; but the basic tenet of this answer is dangerously close to a slippery slope that you do not want to go down. I don’t know how things work south of the border, but up here, all Master’s theses are available and searchable to the public, so you’re quite likely to have someone in the future want to read or quote your paper, errors and all. And if you want it published… best be prepared to proofread all over again! Commented Sep 14, 2015 at 20:50
  • 2
    I am also with @JoeBlow. Most professors I know are actually happy to be corrected and learn a new thing, if done politely. Plus, since this is a minor thing, outside both your areas of expertise, it is unlikely to get anybody upset.
    – Davidmh
    Commented Sep 15, 2015 at 11:21

From Charles Darwin's Origin of Species
From the First Edition, 1859

One of the most remarkable features in our domesticated races is that we see in them adaptation, not indeed to the animal's or plant's own good, but to man's use or fancy.
How fleeting are the wishes and efforts of man! how short his time! and consequently how poor will his products be, compared with those accumulated by nature during whole geological periods. Can we wonder, then, that nature's productions should be far "truer" in character than man's productions; that they should be infinitely better adapted to the most complex conditions of life, and should plainly bear the stamp of far higher workmanship?
but if an occasional cross be indispensable, the fullest freedom for the entrance of pollen from another individual will explain this state of exposure, more especially as the plant's own anthers and pistil generally stand so close together that self-fertilisation seems almost inevitable.
there is a very curious adaptation between the structure of the flower and the manner in which bees suck the nectar; for, in doing this, they either push the flower's own pollen on the stigma, or bring pollen from another flower.
for if you bring on the same brush a plant's own pollen and pollen from another species, the former will have such a prepotent effect, that it will invariably and completely destroy, as has been shown by Gartner, any influence from the foreign pollen.
When distinct SPECIES are crossed the case is directly the reverse, for a plant's own pollen is always prepotent over foreign pollen; but to this subject we shall return in a future chapter.
I can see no limit to the amount of change, to the beauty and infinite complexity of the coadaptations between all organic beings, one with another and with their physical conditions of life, which may be effected in the long course of time by nature's power of selection.
Whether natural selection has really thus acted in nature, in modifying and adapting the various forms of life to their several conditions and stations, must be judged of by the general tenour and balance of evidence given in the following chapters. But we already see how it entails extinction; and how largely extinction has acted in the world's history, geology plainly declares.
This instinct, however, of the American ostrich has not as yet been perfected; for a surprising number of eggs lie strewed over the plains, so that in one day's hunting I picked up no less than twenty lost and wasted eggs

These examples do not include the numerous instances Charles Darwin, the Cambridge educated scientist, and naturalist, used the possessive apostrophe when describing animal features, e.g. Thus, the bat's wing is a most abnormal structure in the class mammalia

  • 9
    A few passages from a single book published 150 years ago is a pretty poor argument. I hope the professor is not convinced by this, although it sounds like he might be.
    – DCShannon
    Commented Sep 14, 2015 at 21:44
  • @DCShannon Charles Darwin is not good enough for you? There are numerous instances where the possessive apostrophe is used that are not related to humans. The link is there, do a search with 's. The OP's professor categorically stated that it is employed only with people. I have provided astounding evidence to the contrary. Darwin an Englishman, a scientist, educated in Cambridge, the father of "evolution", used the apostrophe incorrectly, according to the OP's prof., and you're saying it's a pretty poor argument!
    – Mari-Lou A
    Commented Sep 14, 2015 at 22:05
  • 13
    Yeah, I'm saying that's a pretty poor argument. I would dismiss it out of hand. How Charles Darwin wrote back in the day tells me nothing about what the current professional standards are. I'm not downvoting, since the professor may actually be convinced by this, but there's a much more convincing argument below citing current style guides.
    – DCShannon
    Commented Sep 14, 2015 at 22:16
  • Lewis Carroll's use of is'n't comes to mind... I agree with @DCShannon - single text sources are not good arguments, regardless of their correctness.
    – HorusKol
    Commented Sep 15, 2015 at 6:50
  • 1
    @HorusKol Lewis Carrol and Charles Darwin is like comparing apples and oranges. For other sources, simply pick any English book written in the last five years, and you will find instances where the possessive apostrophe is used for non-human or non-living things. But the prof. might counter-attack that they are examples taken from lazy writers, who know nothing about science and rigour. Would he dare say the same for Darwin? I doubt it.
    – Mari-Lou A
    Commented Sep 15, 2015 at 7:06

Nobody's more standard than Shakespeare, who says:

Shall I compare thee to a summer's day?

Blow, blow, thou winter wind! Thou art not so unkind as man's ingratitude.

How sharper than a serpent's tooth it is to have a thankless child!

More modern examples (and older ones) can be taken from book titles: The Monkey's Paw. Man's Search for Meaning. Cat's Cradle. Childhood's End. Common expressions or terms: In a pig's eye. Tiger's eye (a gem). Dead man's hand. Dragon's Tooth (a rock formation). "Monday's child is fair of face." Bird's eye view, bird's nest soup, bird's nest fungus. Straight from the horse's mouth.

The prof's idea is really indefensible. Nonetheless, proving somebody wrong can be hazardous to your career.

  • 21
    "Nobody's more standard than Shakespeare", umm, you mean the Shakespeare that invented new grammar, hundreds to thousands of new words, and was legendary for abusing language for dramatic purposes?
    – geometrian
    Commented Sep 15, 2015 at 1:08
  • 3
    This answer might be usefull if you quoted it in 17th-century orthography.
    – fdb
    Commented Sep 15, 2015 at 10:16
  • 3
    "Nobody's more standard than Shakespeare" in 17th century English; not modern usage.
    – Davidmh
    Commented Sep 15, 2015 at 11:31
  • 1
    Shakespeare didn't even spell his own name "Shakespeare", it's very risky to cite him as "standard"! Commented Sep 15, 2015 at 14:58
  • 1
    So we have the most acclaimed writer in English agreeing with modern writers and common usage. I think that should be sufficient to answer the question.
    – Maverick
    Commented Sep 16, 2015 at 18:16

Is it really your supervisor you need to impress? Is it not an external examiner? You have put a lot of work and effort into your research, and you obviously care about the quality of your work. I personally would not concede on true quality just to get the thesis 'through the system'.

Having said that, I think that

If the humidity of each plant is displayed publicly...

sounds slightly more formal than your example. That is, removal of the possessive is generally more formal and correct for technical writing. However, it is not always possible, for example where the emphasis is on the possessive (e.g. "plant's own pollen") or simply when rewording might cause too many "ofs" in the sentence!

I'm a native English speaker, and my English is generally pretty good amongst my peers. I'm also writing up at the moment and also have slight disagreements with my supervisor about various aspects (he's usually right...). But ultimately we both know that it is my own research to be assessed by an external examiner.


I'm currently writing my master's thesis in CS and my professor thinks that the apostrophe possessive is only applicable to people. He claims to have spoken to a linguist from Cambridge who confirmed his opinion.

Is it possible that he (or the Cambridge linguist) is confused as to what rule is being discussed? Forming a possessive by appending a lone apostrophe to a singular noun that already ends in "s" is, in some sources, limited to people (or perhaps to the names Jesus and Moses, or only to personal names of multiple syllables according to a certain stress rule - not, say, "James").

This should not be taken to imply that including an apostrophe in the normal 's possessive suffix - or, for that matter, appending a lone apostrophe to a plural noun ending in "s", is likewise limited to people.

Being able to point to a related rule in a style guide that does mention being limited to people may help you convince him that he may have been remembering the wrong rule.

  1. Convert all your possessives to prepositional phrases using "of", e.g., "the bat's wings" becomes "the wings of the bat".
  2. Move on with your life.

You happen to be correct, but sometimes it's best to let the baby have its bottle.

  • 1
    The question was "How do I convince my professor?"
    – Andrew Leach
    Commented Sep 14, 2015 at 21:58
  • 3
    And the answer is, "Don't".
    – einnocent
    Commented Sep 14, 2015 at 22:28
  • 4
    Come to think of it, this isn't a grammar/usage question at all. Perhaps it should be migrated to a psychology or management forum.
    – einnocent
    Commented Sep 14, 2015 at 22:30

I think there may be some confusion between two different things:

  1. The genitive suffix 's.
  2. Using nouns as adjectives.

Each of your examples can be written using noun strings - the nouns that function as adjectives are in italics:

  • If each plant humidity is displayed publicly [...]
  • [...] shows an overview of the node structure.
  • Due to an issue in the network stack IPv6 subsystem [...]

Both styles are standard English, but noun strings can't be used for plurals like "the plants' humidity is displayed" (i.e., one humidity value is displayed for many plants), and long noun strings like "the International Space Station astronaut accommodation module development project proposal" are hard to read unless you are familiar with the terminology being used.


  • 6
    the node structure and the node's structure is two very different things. One talks about how nodes are connected the other talks about what is going on when you remove the abstraction that hides the internals of the node.
    – Taemyr
    Commented Sep 14, 2015 at 18:15

"Examples of phrases:

If each plant's humidity is displayed publicly [...]
[...] shows an overview of the node's structure.
Due to an issue in the network stack's IPv6 subsystem [...]"

These examples are all good English.

  • 5
    And how exactly is this meant to convince the OP's professor? Commented Sep 14, 2015 at 13:04
  • 5
    Maybe if he told him he heard it from a "linguist in Cambridge".
    – fdb
    Commented Sep 14, 2015 at 13:06
  • 7
    How about a linguist from Michigan? (actually I'm retired now and live in Washington state, but I taught linguistics and English grammar at the University of Michigan for 37 years, and published a number of studies on the subject.) While it's true that mostly the Saxon genitive applies to humans and the Romance genitive to things, this is just a rule of thumb. In the example sentences given, @fdb has it right -- they are all good, proper, formal English sentences; whereas their transforms with Romance genitives are not improvements, and are often awkward and unnatural. Commented Sep 14, 2015 at 14:26
  • 5
    If your professor wishes to contact me, I will go into detail (if provided with more detail first). Commented Sep 14, 2015 at 14:26
  • 3
    @fdb Utter nonsense. Critique is a perfectly good English verb. Commented Sep 15, 2015 at 13:34

Not the answer you're looking for? Browse other questions tagged or ask your own question.