Example with a context (The Object-Oriented Thought Process by Matt Weisfeld, 3rd Edition):

We see this all the time when using a cell phone.To make a call, the interface is simple—we dial a number. Yet, if the provider changes equipment, they don’t change the way you make a call. The interface stays the same regardless of how the implementation changes. Actually, I can think of one situation when the provider did change the interface—when my area code changed. Fundamental interface changes, like an area code change, do require the users to change behavior. Businesses try to keep these types of changes to a minimum, for some customers will not like the change or perhaps not put up with the hassle.

As far as I know, for is a very old-fashioned way to say because (this type of for is often found in the King James Bible) which is what most English-speaking people nowadays use to mean that something happened for a certain reason and then they explain what that reason was. I have really never heard in real conversation anyone say for to mean because. And it actually makes perfect sense. For one thing, for has been firmly established as a function word that indicates purpose whereas because means for the reason that. Mixing the two up in daily language can make people give you strange looks. You don't say:

I didn't go to school today for I felt ill.

That would probably sound weird. You say instead:

I didn't go to school today because I felt ill.

So, my question is why do some authors tend to use for when they could simply use because which nobody would have a problem understanding? To me, it sounds like this kind of usage of for in place of because is absolutely unwarranted, although I can imagine somebody using for like that if they were writing a play where the scene took place in medieval England and they wanted to give their language a certain archaic feel.

  • 5
    I (native AmE speaker) personally use "for" to mean "because" sometimes when writing, particularly when writing more formally. It's not something I'd expect to hear in conversation, but it's not that weird in writing (which a book obviously is), and it's absolutely not archaic.
    – cpast
    Commented May 9, 2015 at 5:16
  • 2
    There's competition between "because"/"for"/"since"/"due to"/etc., and sometimes one has advantages over the others. There's the classic ambiguity in "I didn't go to the party because Sue was there"; using a different phrase to replace "because" can sometimes remove that ambiguity. Actually, your example "I didn't go to school today because I felt ill" has that ambiguity problem--e.g. "I didn't go to school today because I felt ill. For/because I'm not that kind of person who would want to make my classmates get sick. I had to go to school today because I had a test." :)
    – F.E.
    Commented May 9, 2015 at 5:46
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    @F.E. I'm not sure If I see the ambiguity in either of those sentences.
    – DJMcMayhem
    Commented May 9, 2015 at 7:23
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    @DJMcMayhem The first reading is the one where I didn't go to school. The second reading is the one where I actually did go to school. It's a little harder to come up with a context where the 2nd reading is reasonable for the OP's example, but it is doable (imo), e.g. a context where the mom accuses her daughter of wanting to go to school specifically to spread her illness which the daughter thought she might be getting. This specific type of ambiguity that "because" is known to have is often documented in general use dictionaries in their usage notes to "because". (cont.)
    – F.E.
    Commented May 9, 2015 at 16:01
  • 2
    @DJMcMayhem For instance, in this dictionary, New Oxford American Dictionary, there is this for their entry "because": usage: 1 When because follows a negative construction, the meaning can be ambiguous. In the sentence he did not go because he was ill, for example, it is not clear whether it means either ‘the reason he did not go was that he was ill’ or ‘being ill was not the reason for his going—there was another reason. ...’
    – F.E.
    Commented May 9, 2015 at 16:04

4 Answers 4


I could not find anything better than this on Dictionary.com

It says that 'for' in such context has been used as a conjunction meaning 'because, since'. It's old usage of the word 'for'.

[Middle English, from Old English; see per in Indo-European roots.]

Usage Note: 'For' has been used as a conjunction meaning "because, since" for over 1,000 years. It is familiar in many famous quotations, from the New Testament's beatitudes (Blessed are the meek: for they shall inherit the earth, Matthew 5:05) to Shakespeare's sonnets (For thy sweet love rememb'red such wealth brings / That then I scorn to change my state with kings).

Today this use of for is rare in speech and informal writing, and it often lends a literary tone or note of formality. · Like the word so, for can be viewed as either a subordinating or a coordinating conjunction, and it has been treated variously as such. It has the meaning of a subordinating conjunction, since it clearly subordinates the clause that follows it to the previous clause or sentence. But like a coordinating conjunction, for has a fixed position in the sentence, and its clause cannot be transposed to precede the superordinate clause containing the main idea. It is ungrammatical in present-day English to say For they shall inherit the earth: blessed are the meek. Perhaps because of this ambiguity in function, for is treated variously with regard to punctuation. Sometimes it begins a dependent clause and follows a comma, and sometimes it begins an independent clause (as if it were a conjunctive adverb like moreover) and follows a semicolon or period (when it is capitalized as the first word of a new sentence). All treatments are acceptable in standard usage. The difference is really one of emphasis: starting a new sentence with for tends to call more attention to the thought that it introduces.


I didn't go to school today for I felt ill.

is not weird because you want to say that you did not go to school today because/since you felt ill.


I find that the word "for" asserts a causal relationship less strenuously than "because". Its use has been on a fairly steady decline since the 18th century, yet it is hardly to be regarded as obsolete, for it fits in quite well with a semi-formal style where we find many turns of phrase which are neither archaisms nor examples of today's passing fads.

  • An example of the greater strength of "because" might be, "The T.V. is off because I turned it off." You wouldn't say, "The T.V. is off, for I turned it off." "For" is no good at emphatic tautology. Commented May 24, 2015 at 1:47
  • In conversation, I'd use "since" in constructions like the one in my answer; "since" is also wimpish compared to "because": "The TV's off since I turned it off."
    – TimR
    Commented May 24, 2015 at 11:27

I think that you could use either "for" or "because" for most anything that works for either one and it should be right even if it sounds weird. Though usually nowadays you only use "for" when further describing the previous noun rather than brining up a new noun in an explanation. Ex. - The plant was not a tree, for trees have leaves and the plant didn't. When using "for" to bring up a new point, as a reason, that doesn't reference the previous noun it sounds a little more funky. Ex. - I didn't go to school, for I was sick. I think this is due to "for" meaning the expounding of reason or use nowadays, applying that connotation to the other function. Ex. - The wrench is for my bike. In all fairness "for" just sounds weird in all conversation and "because" is probably the right choice (because/for) it works in both examples just fine.


I find the difference more one of clause construction than meaning, similar to 'that' and 'which'. For example, the following sentence is ambiguous, unless a comma is added:

I didn't [go to school today because I felt ill].

I didn't [go to school today], [because I felt ill].

However, the same sentence using 'For' has no need for a clarifying comma:

I didn't go to school today for I felt ill.

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