I am sure we all have heard, at some point, someone saying, 'I have a theory about X. I think....'. I have realized now that actually, a theory is a system of ideas that has been verified systematically (/experimentally) to be an explanation of some phenomenon, like the theory of gravitation. Therefore, the word should not be used so loosely as is done in popular culture today.

I realize that this meaning of theory, as 'an idea used to account for a situation or justify a course of action' is recognized, but especially when talking in a scientific context, it seems somewhat inappropriate to use it with that meaning - since I am using also that word for meaning something far more specific. Also, the fact that there are dozens of websites claiming this use to be somewhat incorrect, has some significance.

Moreover, Merriam-Webster notes -

However, there are two senses of theory which are sometimes troublesome. These are the senses which are defined as “a plausible or scientifically acceptable general principle or body of principles offered to explain phenomena” and “an unproven assumption; conjecture.”

So my question is, what would be a better replacement, in a situation where someone is trying to pose his/her "theory" about something? I was initially thinking using idea, but it lacks the sense that it's supposed to be an explanation. I was also thinking something like hypothesis or conjecture, but I wasn't sure.

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    Comments are not for extended discussion; this conversation has been moved to chat.
    – tchrist
    Commented May 21, 2017 at 3:26
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    "I have a theory that ..." on the Clapham omnibus would be taken as meaning "My suspicion / explanation is as follows: " 95+% of the time. Commented Jan 14, 2021 at 14:56
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    Someone saying 'my theory...' is already context enough to infer that it is their own informal personal conception of things.
    – Mitch
    Commented Jan 14, 2021 at 21:56

4 Answers 4


The word theory has multiple meanings. There is the common usage which means, as you suggest, hypothesis or conjecture and there is the scientific definition which means "that's the fact, Jack."

I always use hypothesis precisely because of this so as to avoid any confusion (and am trying to teach my kids to do the same.)

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    'That's the fact as received scientific wisdom sees it, Jack.' The flat-earth theory once held sway. // Always using 'hypothesis' may alienate a fair number of people. I'd argue that intelligent people should be ready to adjust register. Few would even raise an eyebrow to "I have a theory that most sightings of the Loch Ness Monster are actually catfish-, eel-, shark- or hoax-related". Commented Jan 14, 2021 at 15:11
  • @EdwinAshworth - I agree that intelligent people should be able to determine the meaning via context but, outside of this forum, there seems to be distressingly few such people. The issue often comes up in the context of "evolution is just a theory!" which is true -- it is a theory but with the scientific meaning. Alas, too many people, intentionally or ignorantly, apply the common usage in that context. Hence my preference for hypothesis. Commented Jul 23, 2021 at 17:58
  • @EdwinAshworth - Note that my comment above pertains primarily to the US; elsewhere in the world people seem to be better educated and more inclined to the use of logic. Commented Jul 23, 2021 at 18:00

Hypothesis is good for more formal situations, as Roger Siashon says. A hypothesis is something that may become or form the basis of a theory if it's verified via measurement.

Less formally, you could use: idea or even suspicion (if you're really uncertain about it) interchangeably in your example.

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    thanks Benjamin, but i feel that idea/suspicion does not have the sense of explanation, as in I think X could explain this situation at hand. what do you think?
    – user1995
    Commented May 17, 2017 at 6:40
  • You're right for some cases. I'd put suspicion, idea, and theory on a spectrum of less sure/less detailed to more sure/more detailed. For some specific cases - where I'm proposing a way of explaining/modelling something - I often find myself using 'pattern' or 'model', as in "If we model this as a set of x's" .This suggests that it's a useful explanation as rather than attempting to be a complete explanation. This is in a software setting though - may or may not be useful to you.
    – Beejamin
    Commented May 17, 2017 at 6:57
  • "Suspicion" as in "I have a suspicion that John murdered his wife and threw the body in a bin" is an explanation for her absence. I don't see why you need something more specific: "I have a suspicion and I think this is an explanation: John murdered his wife and threw the body in a bin" although you might say what it is an explanation for.
    – Stuart F
    Commented Dec 16, 2022 at 11:33

I think these words can convey the sense of "supposed to be an explanation, but not verified yet":

  • hypothesis
  • explanation
  • account
  • model
  • framework
  • reasoning
  • rationale
  • justification

Or you can simply use "unverified theory"

In addition, you can also use these words, but for me they emphasize the connotation of a subjective interpretation rather than an unverified theory, though can be served as a way to explain things:

  • opinion
  • approach
  • consideration
  • assumption
  • interpretation
  • point of view
  • perspective
  • worldview

In general conversation, instead of “I have a theory about X”.

I now say “I have a couple of ideas about X” or “I have a hypothesis as to why people think X” or “I have some thoughts about X”.

I’m not often hanging around with scientific people or colleagues, rather I simply prefer to use my words correctly, improve myself. That, and I’m frightened by the number of mean, condescending comment replies I’ve seen online where one individual feels the need to correct another’s spelling or incorrect word usage.

Thank you to all of the contributors above. I really appreciated all of your responses. They went from everyday usage to academic usage, as well as discipline specific usage. Simply wonderful, each and every one. Thanks again.

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