‘Aristotle was great’. Is this a statement?

I consider a statement to be something either true or false (but not both).

For an individual, this may be considered a statement (because either you think the statement is true or it is false, assuming that an indifferent opinion is counting as thinking he is not great).

However, as a collective, this may not be considered a statement because some people will say its true and some will say its false, going against the definition that a statement cannot be both.

So, is ‘Aristotle is great’ considered a statement?

  • 2
    You are confusing math terminology to the real world. A statement doesn't have to be true or false. Some statements are meaningless for instance. Propositions are what is expressed to be true or false. Propositions are ideas in the mind expressed through a language for others to know the idea. This means meaningful declarative sentences in English. So you may hear people say declarative sentences are true or false. Propositions are not sentences. Sentences can be seen, written, etc. An opinion in many cases is a statement. "Mayweather is the best pound for pound boxer ever" is a statement.
    – Logikal
    May 28, 2020 at 19:05
  • 1
    Interestingly, this question was sparked from a book of mathematical thinking (but didn’t think this question would be entirely appropriate to the maths stack exchange) It is quite interesting to see the varying viewpoints from a mathematicians viewpoint and one of a philosopher. May 28, 2020 at 19:09
  • A statement in logic is something that is unambiguously true or false. It doesn't matter if it is only an opinion (because we do not know, or even can not know), but its truth/falsity has to be, in principle, definitive. Sentences involving vague predicates, like "great", "beautiful", "interesting", are not statements in this narrow sense. When someone says "Aristotle was great" they are typically not applying any definitive criteria, even subjective ones, but only conveying a vague impression. In contrast, "Aristotle was heterosexual" is a statement, even though we'll never know for sure.
    – Conifold
    May 28, 2020 at 22:11
  • I like your way of thinking. "In mathematical logic, a sentence of a predicate logic is a boolean-valued well-formed formula with no free variables. A sentence can be viewed as expressing a proposition, something that must be true or false." en.wikipedia.org/wiki/Sentence_(mathematical_logic)
    – polcott
    May 30, 2020 at 15:35
  • This means that a statement must definitely resolve to true or false, matters of opinion to the contrary carry no weight. Before Pythagoras everyone in the world agreed that the Earth is flat. We know now (from pictures from space) that the Earth is spherical, none-the-less prior statements were eventually resolved to definitely false.
    – polcott
    May 30, 2020 at 15:38

5 Answers 5


Statements (as Kant suggests) have the form subject + predicate. Following the systems theory, this is essentially a semantic interrelation between two systems, which in this case are concepts:

[Aristotle] <--> [Great]

Statements have necessarily such structure. The rest of the elements of a sentence are just the syntactic and lexical auxiliaries. "Jogging" or "tea" are not statements, just concepts.

Moreover, a) the relationships within a sentence are formed not by two systems, but properly, by a subject and an object. No statement exists that don't relate a subject and an object. It could seem that statements like "GOTO 10" (a Basic programming language statement) or "Walk!" don't relate two systems, but that's just apparent. b) The relationships are just interactions (or interaction sets) between the two objects. c) Subject + Predicate means that the predicate is formed by an interaction (or relationship) and an object. Concepts, predicates, subject, object are deeply analyzed in Kant's Critique of Pure Reason.


  • "Walk!" is an imperative sentence. This is equivalent to say "You, walk". We don't say "You" because of the language structure, which makes that unnecessary: the subject in an imperative is always the person target of the imperative command. Now, which is the object? When we act, we don't just act. When we clean, we need to clean something. Walking is the same: we act over something. When we walk, we can say that "we walk the walk". Therefore, this sentence is telling "You (subject), do walk (the walk)". The interaction is the first walk.

  • "GOTO 10" is telling the computer (subject) to GO TO [line 10] (object). The relationship or interaction is "going". This is another example of imperative.

  • "Hello" probably means telling "I (subject) am starting the communication with YOU (object)". (And "bye" is used to close the communication)

  • "Please close the door": Subject is you, object is the door, the interaction between both systems, you, and the door, is the act of opening.

  • "Aristotle was great": this is equivalent to say "there's an interaction of the type 'being' between the subject Aristotle and the object Greatness".

Now, to answer your question: opinions have the same structure as propositions and statements. When you say that something is "true or false" you are not adding any valuable information. That's like saying that things are heavy or not. The degree of falsehood or truthfulness is irrelevant. So, they are effectively statements.

  • You are confusing declarative sentences with statements. Just because statements have the form subject + predicate, it doesn't mean that all sentences of such form are statements. In logic, statements are declarative sentences that are either true or false but not both. "Aristotle was great" is a declarative sentence but it is merely an opinion with no definite truth value. To say something is heavy or not is an opinion just the same.
    – gadfly
    Jun 8, 2020 at 17:30
  • @gadfly, any type of sentence carries information, regardless of the communication sense. My examples deal explicitly with imperatives and declaratives, but might work well for exclamatives. In any case, I'm not only addressing specific types of sentences, but all statements in general, which are the OP's target.
    – RodolfoAP
    Jun 8, 2020 at 18:00
  • What you say is irrelevant. Imperatives are not statements. Some declarative sentences are statements and some are not. statements ⊂ declarative sentences ⊂ sentences. Imperative sentences ⊂ sentences. Imperative sentences ⋂ statements = ∅.
    – gadfly
    Jun 8, 2020 at 20:14

There is a basic confusion in your question: one thing is whether a proposition is true or false, and a very different thing is the fact that some people think it's true and other people think it's false.


A statement (in the logical sense) is merely an uttered proposition that has a truth-value. That does not imply that we know what the truth-value is; it only implies that ideally we could know whether it was true or false. If I were to say "unicorns have blue feathers", that would be a statement because potentially we could determine whether it was true of false: e.g., if we found a unicorn somewhere and it did not have blue feathers, the statement would be false.

With a evaluative statement like "Aristotle was great" we have a separate problem that we first need to decide what we mean by 'great' in this context. If we do not have an effective definition n of what it means to be 'great' in this context, then the statement has no truth value, and is an empty utterance (as empty as saying, say, "Aristotle was plufloric"). If we have an effective definition for 'great', then it becomes possible to establish the claim's truth value, so it is a valid statement.


When we look at whether a sentence is a statement or not the important thing is whether we know it is true or false (even if we don’t know which), whether it is in principle testable, and whether it is actually clear. “Aristotle was great” isn’t very clear. What exactly does it mean? Two people with good knowledge about Aristotle could easily disagree. “Aristotle was 6’3” ” is much better in that respect.

When we look at whether a statement is an opinion or more, it depends on how that statement was created. An”opinion” Is mostly something that I just made up in my mind without reasonable fact checking. So opinion can be a statement or not.


Strictly speaking it's an opinion and not a statement, unless there is some specific unambiguous definition of "great" that is all agreed on. Just like sentences such as "John is smart" or "Ann is pretty" are opinions and not statements, unless there are specific unambiguous standards of "smart" and "pretty", resp.

  • Interesting. What is the "unambiguous standard" for 1 meter? Being the standard for 1meter = 1.000000000(infinite number of zeros)m, a ruler measuring 1.00000002m is not a "one meter ruler". Therefore, saying "this ruler measures one meter" is in all cases an opinion, and never ever a statement, since one can always find an ambiguous value just by using more digits. Conversely, if you accept that a meter is a range around 1+/-0.0001m, is that a standard? Accepted by which standards association? You mean that statements don't exist?
    – RodolfoAP
    Jun 8, 2020 at 20:38
  • Futile for me to continue here. I refer you to some introductory logic books. Also, the comment by Conifold above is close to what I mean, with the exception where he/she said it doesn't matter if it's an opinion.
    – gadfly
    Jun 8, 2020 at 23:22

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