I'm looking for a word or phrase that describes a statement that is neither a scientific fact nor an opinion. Google defines opinion as "a view or judgment formed about something, not necessarily based on fact or knowledge" but I'm looking for something that is based, at least indirectly, on knowledge.

For example, if I believe it is pointless to brush teeth in the morning since no food has been eaten since the previous night, what would this statement be called? I don't think it's a scientific fact since no studies or experiments have been made to prove it, but I don't think it would be called an opinion either, because it is at least logical. Would it be correct to call it a philosophy?

Another example I came across is as follows: one person was arguing that if a person (i.e. a hacker) was trying to guess the password to something, nothing is known about which order or which passwords they would try. Therefore, having minimum requirements for passwords is pointless (e.g. "8h4fhA" may seem like a more complex password than "apple", but technically there's no guarantee a hacker wouldn't test "8h4fhA" first). Would this be an opinion or fact or something else? While the premise seems true and the conclusion logically follows, I personally disagree; for example, it seems much more likely a person would guess "password" (or something easy) than "8h4fhA".

Another good example is deciding which car to buy. It's a matter of opinion which car is better than others but at the same time there are facts and reviews that can back up claims so it's not purely opinion.

A general example is when experts in an area disagree on a subject, for example if eating cheese before going to bed helps sleep. If one scientist claims that it does, should this be referred to as his opinion since there are other scientists and studies done that show that it does not?

  • Just a note: I don't agree with the idea that calling something an opinion negates all factual content and logical validity of that belief. Opinions can coincide with facts. Opinions can be well-researched and logical. Opinions are rarely spun out of thin air with no support. By calling a belief/idea/statement an opinion, you are doing two things: 1) associating it with the beliefs of a particular entity 2) acknowledging the possibility of refutation. All these examples could still be called opinions.
    – Solocutor
    Mar 31, 2016 at 16:41
  • Fact: There's no such thing as a "fact".
    – Hot Licks
    Nov 16, 2016 at 1:46

7 Answers 7


A hypothesis is a guess, based on data or logic of some kind.

So, if your hypothesis is: It is pointless to brush your teeth in the morning because no food has been eaten, not eating serves as the logic that bolsters your guess.

For a hypothesis to be viable, it needs be testable.


Theory comes to mind

An assumption based on limited information or knowledge; a conjecture.

Synonyms: hypothesis, thesis, conjecture, supposition, speculation, postulation, postulate, proposition, premise, surmise, assumption, presupposition;


How about assertion or argument.


From your question,

"If one scientist claims that it does, should this be referred to as his opinion since there are other scientists and studies done that show that it does not?"

I would say if a mathematician or a scientist claimed such a thing, it would be called a conjecture.

From Oxford Dictionaries,

an opinion or conclusion formed on the basis of incomplete information:
conjectures about the newcomer were many and varied

[mass noun]:
a matter for conjecture

  • an unproven mathematical or scientific theorem.
  • [mass noun] (in textual criticism) the suggestion of a reading of a text not present in the original source.

An informed opinion

  • Word-crafter‎ An informed opinion is based on knowledge of the facts and carefully considered principles. It relies on evidence instead of limited personal experience.

Depending on the context, the aforementioned "Conjecture" is probably most accurate.

I'll note this part, though:

}}} Therefore, having minimum requirements for passwords is pointless

is blatantly fallacious. It is based on presumptions about how password attacks work which are just simply wrong. One of the prime methods to crack a password includes something called a "dictionary attack" which is to (accurately) presume that people are wont to use words that have meaning in their heads rather than random characters. So they're MUCH more likely to use "doggie" than "d292k2". So one of the FIRST things that are done to initiate an attack is to throw a list of the 100, 500, or 1000 most common words people use for passwords. A computer can do that in as little as seconds.

The best system I've ever seen for creating a password is to have four components, upcase, lcase, number, symbol, and vary one of them consistently, while holding the others fixed (order can change, of course). Make one of the Ucase/Lcase fairly long, and construct it as follows:

-- Pick a song you know particularly well, e.g. (but not) "Yesterday": 'yesterday, all my troubles seemed do far away, now it looks as though they're here to stay' -- and take the first letter from each word of the lyric, to wit: YAMTSSFANILATTHTS (note, you can use later lyrics, too, not just the obvious first one, even better). And you can see this is as pretty close to a random letter sequence as you can get. But you should have no trouble recalling it on demand, even weeks from now. Use that to pad out your constructed password (remember, that's only one of the four parts) to as long as you're willing to type (more is definitely much, much better). A 20-30 character password that you easily remember is pretty easy to construct like this.


As long as the discussion revolved about a "scientific" way of knowing something, that is, how reliable the statement is, there is a hierarchy of terms. "Law" is widely and completely accepted, usually for many years or decades, as reliably true. Think Newton's laws of motion. "Theory" is a bit lower on the scale. Think Einstein's Theory of Relativity. "Hypothesis" is, again, lower on the scale.

For most scientists, hypothesis is the first formulation of their understanding of how the universe works. They have observed lots of data happening around them and want to use these in an organized concept of how the universe works. For this to proceed, they need to test the hypothesis against two standards: 1. Can an experiment show the hypothesis does NOT explain the data (this is called "falsifiable"). 2. Can an experiment predict an outcome (this is called "testable").

Darwin's explanation of Evolution has not gained the prestige of a Law because any experiments for Testability or Falsification would take so long (and be so expensive) to carry out.

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