Student Stumper 32: Can TO and FOR both express purpose?

QUESTION: Should I say that a knife is used to cut things or for cutting things? Can both TO and FOR express purpose?

ANSWER: This was a question posed by a YouTube viewer. I responded by acknowledging that both forms were possible in the given example. I speculated about differences in context, but I didn’t explore them. I think my initial answer needs to be expanded on.  I’ll first turn to a trusted source for insight.

In their discussion of gerund and infinitives, Azar and Hagen note the phrase be used for and tie it to the purpose of an object (331). For example, a butter knife is not used for slicing. It’s only used for spreading butter on bread. However, they note that an infitive of purpose is also possible to express a general purpose: A butter knife is only used to spread butter, not slice things. A good distinction Azar and Hagen make is that only an infintive of purpose is used in a specific context: I had no knife, so I used a spoon to spread the butter on my bread. (“For spreading” cannot substitute.)

I’d like to go beyond structure and consider semantics. I think we can further define purpose. Do we mean reason  or intention? To explain why something happened (reason), we can use for + noun/pronoun object: He received a medal for his bravery. / He gained recognition for his heroic acts. To explain what someone hoped to gain from doing an action (intention), we can use an infinitive: He put his own life in danger (in order) to save his comrades. I find it difficult to paraphrase this last example so that it includes for + a noun object. Would we say “for the safety and survival of his comrades”? It’s possible, but it sounds wordy to my ears. I prefer the simplicity of the infinitive “to save his comrades.”  I think then we might be able to conclude that there are more frequent or preferred patterns when it comes to expressing reason or intention.

A final definition of purpose could be a goal, that is, what a person wishes to obtain. In such a situation, I think either an infinitive or for + noun object could be used: I returned to school for a degree in marketing. / I returned to school (in order) to receive a degree in marketing.

What are your thoughts? Do you think the difference between an infinitive of purpose and for + gerund/ noun object goes beyond form?


Azar, Betty S. and Hagen, Stacy A. Understanding and Using English Grammar. Pearson Longman, 2009.

12 Comments Add yours

  1. nliakos says:

    I find that students often prefer for + Ving in cases when I think it just sounds wrong. I tell them to use the infinitive instead. However, I have to admit that in some cases, such as in your examples, for + Ving is acceptable. I had not thought about the specific context requirement before.

    I always consider purpose to mean goal or intention. The confusion is due to the fact that the same question word (why?) is used to ask about reason and purpose. “Why did you come here?” can be answered as well with “because my parents made me” as it can with “to get an MBA”.

    I love infinitives and infinitive phrases and enjoy sorting out their many functions (adjectival, adverbial, purpose, subject of clause, object of certain verbs…). They are so flexible and can be used in so many ways!

    Happy New Year!

    1. Happy New Year to you, Nina. 🙂

      You bring up a good point. In English “why?” can have more than one meaning. In other languages (Russian, for example), there are two different interrogative words to express “for what purpose” and “for what reason.” Perhaps this is a case where simplicity in English actually creates ambiguity. Ah, grammar! So much to talk about…

  2. jusman says:


    I like all your videos, May I download them?
    My pronunciation is not good like you. . .

    I want to improve English in my school and other places in my province through your video.

    Jusman S.Pd

    1. Yes, you can download the videos. Look on my channel and view my favorites. I include two tutorials on how to download the videos from YouTube.
      Good luck to you!

  3. Hi,

    Dear teacher thank you very much for the entire marvelous effort to help students as well as teachers in learning English language. I my case it is not only learning English language but a complete career. i was unknown to English but living with the thrust of learning English. your site helped me achieving the goal of my life. now i have established an English Language Center in one of the cities of Pakistan. students are getting benefits a lot. let me say it is because of you.

    God bless you


    your student

    Syed Wali Shah

    1. Hello! Congratulations on opening your own English Langauge Center! That is a major undertaking.
      I’m honored that some of my materials and ideas have been incorported into the instruction you provide.
      Warm regards to you and your students!
      – Jennifer

      1. Syed Wali Shah says:

        It is really honor to get your reply. Thank you so much again

  4. Issa Danilovic says:

    Thank very much for your incite. I still cannot say that I fully understand the diffence not because of any short comming on your part but because I believe this issue is contains a lot of subtle complexities that are not easily defined.

    1. Indeed, is there any one person with all the answers? I’m in search of many answers about a great number of topics related to our work, and that’s one reason why I continue to write here on my blog!

  5. sara says:

    hello jennifer i would like learn english
    Iam speak Arabic

      1. sara says:

        thanks jennifer for quick response

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