there is no opposite to "possible". And to use "impossible" as the opposite to "possible" is to stray from the definition "what may or may not be". — Metaphysician Undercover

I use a different definition, but the ends are the same. — Mww

So if I have a stack of boxes, and I'm going to mark one of them with an X, then it is true of each of the boxes that it may or may not be the one I'm going to mark. Once I have marked a box, it is no longer true of any of the boxes that it may or not be the one that I'm going to mark: it is true of one that I have marked it and of the others that I have not, and that's it.

As a temporal sort of modality, that seems fine. Once I have marked a box, would either of you say that it is true of each of the other boxes that, though it is not the box I marked, it might have been the one that I marked? If actuality is the closing off possible futures, can we not imaginatively consider an early time at which the actual present was only a possible future, one among many?

Above I spoke hypothetically of having a stack of boxes one of which I intended to mark. How do you conceptualize what we are doing when we reason in this way? Am I talking about a possible future in which I do have a stack of boxes?

Thanks for the gentle correction.

And.....what benefit in them is there for me?
— Mww
— Srap Tasmaner

If I know that P, then it follows that P. That’s helpful for you, because it means you can learn about the state of the world from my reports of what I know, without having to go see for yourself. — Srap Tasmaner

Helpful, I suppose. If your P is the bridge is out, and the bridge is out....might be helpful fo me to know that iff I’m on the road the bridge is out of. If I’m not even driving....your P tells me about a state of the world for which I have no interest, hence is not helpful.

But I get the point.
————

Above I spoke hypothetically of having a stack of boxes one of which I intended to mark. How do you conceptualize what we are doing when we reason in this way? — Srap Tasmaner

Intention alone cannot afford an determined end, that isn’t a potential post hoc ergo proper hoc logical subterfuge, yet herein we’re providing an exercise for imagination, which can. What we should be doing, so says this armchair (which after all these years has earned the right to speak for itself).......mark a box or don’t, leaving intention out of it, or on the other......intend to mark a box, leaving a marked box out of it.

As stated, I can’t conceptualize what we doing, insofar as it appears we’re operating under two separate and distinct conditions forced somehow into relating to each other.

We don't know with deductive certainty. But that's not the relevant or appropriate standard. The relevant standard is to look out the window and see whether it's raining.
— Andrew M

But this is just going around in a vicious circle. The example says that someone might be hosing the window. So according to the example, looking out the window doesn't give us the certainty required to know whether it is raining. — Metaphysician Undercover

Not deductive certainty, certainly. In the window hosing scenario, Alice would need to look again, or more carefully. But that doesn't preclude her from having knowledge when it is raining, as long as she does look.

From the earlier Gilbert Ryle quote: "All it requires is what familiar facts provide, namely that observational mistakes, like any others, are detectable and corrigible; so no empirical fact which has in fact been missed by a lapse, need be missed by an endless series of lapses."

On factive verbs, or, ordinary language use gone irredeemably haywire:

“we believe every foot deserves a comfortable pair of shoes”

....says so, right on the door into the self-proclaimed oldest shoe store in America, opening in 1832 in Belfast Maine.

What can ya do, huh?

The gist of which is that if I see that it is raining, I also thereby know that it is raining. If I remember that I have an appointment, then I thereby also know that I have an appointment. — Srap Tasmaner

Yes, that's right.

— Insofar as the point being made by Mww is about our conceptual apparatus and its role in our mental acts, I’ve got nothing helpful to say about that. — — Srap Tasmaner

In knowledge-first terms, I know it is raining because I already know what it is to be raining.

A precise reduction to the thread’s original question. I know what is true because I already know what it is to be true. I know what is true because I already know what truth is. — Mww

@Mww's comment reminded me of your earlier comment on a priori and a posteriori.

That is, we already know what it is to be raining. When we look outside and see that it's raining, we are identifying what we see with our idea of what it is to be raining, and labelling it accordingly.

Similarly, we already know what it is to know something, the rain scenario being a typical example.

From there, we can think of ways that someone can fail to know something, say, because they haven't looked out the window. In that case, we suppose it's nonetheless raining or not (just as to count the coins in the jar entails a prior number), so we use the terms "true" and "false" to register that idea ("to say of what is that it is ..."). They may then go on to discover the truth of the matter ... by looking out the window. [*]

So knowledge is the intended target, with truth defined in terms of it. (@Banno) From Williamson:

Most epistemologists agree that while knowing entails believing truly, believing truly does not entail knowing. Someone does not know something he believes truly on the say-so of his guru, who invents things to tell him at random without regard to their truth or falsity. Although merely believing truly involves a sort of success—getting the answer right—it also involves, unlike knowing, a sort of cognitive malfunction. Thus knowledge is a more full-blooded success condition than true belief. Knowledge first epistemology understands cases of cognitive malfunctioning in terms of their deviation from cases of cognitive functioning, as opposed to treating the two kinds of case more symmetrically. — Knowledge First Epistemology, Timothy Williamson - The Routledge Companion to Epistemology

--

[*] Where discover is yet another factive verb. It's easy to see how the acceptance or rejection of factivity leads people in philosophical threads to literally talk past each other.

On fictive verbs, or, ordinary language use gone irredeemably haywire — Mww

Factive, fractive, fictive ... ;-)

factive
/ˈfaktɪv/
adjective LINGUISTICS
denoting a verb that assigns the status of an established fact to its object (normally a clausal object), e.g. know, regret, resent.

Spellchecker. That’s my story and I’m sticking to it.

When I say "the book is possibly in my room" I'm not saying "the book isn't actually in my room". — Michael

As I said, the two (possible and actual) are not opposed to each other. But obviously, saying "the book is possibly in my room", is to say something completely different from saying "the book is actually in my room". I think you'll agree that these two each say something distinct. And what I am saying is that the two beliefs expressed with these sayings are not consistent with one another. If you believe the book is possibly in your room, you do not believe that it is actually in your room. And if you believe that it is actually in your room you do not believe that it is possibly there.

To assert that the book is possibly in your room when you beilieve that it is actually in your room is to be dishonest. And, to assert that it is actually in your room when you think that it is possibly in your room, is to be dishonest. That these are instances of dishonesty indicates that the two are incompatible with each other.

I admit that there is a way to formulate things, so that we say that one of the possibilities is what is actually the case (one of the possible numbers is the actual number of coins in the jar). But as I explained earlier, this is just based in the assumption that one might be determined to be the actual. It doesn't mean that one already is the actual, because that would be deceptive. They must all be equally possible, and when one is determined as the actual, then all the rest lose their status of "possible", and therefore become impossible. So no matter how you look at it, one cannot be the actual while the rest are possible. They must be all possible without an actual, or one actual and the rest impossible.

Otherwise telling you where something might be is telling you where not to look.

Your position doesn't appear consistent with common use. — Michael

In common use, telling me where something might be, is completely different from telling me where it is. And if you know where it is, and I ask you, and you tell me "I don't know where it is, but I know where it might be", you are being dishonest. Likewise, if you don't know where it is, but know where it might be, and you tell me you know where it is, you are being dishonest. Clearly, it is your position which is not consistent with normal usage. Common usage demonstrates a healthy respect for the difference between what is actually the case, and what is possibly the case. And we do not mix these two up, to say that we think something is possibly the case, when we believe that it is actually the case, or vice versa.

I use a different definition, but the ends are the same. Possibility is merely one of the ways to think about things; a thing is possible or that thing is impossible, but that does not make the conceptions themselves opposites. All they do is condition the thought of the thing. Just as cause is not the opposite of effect; just as necessary is not the opposite of contingent. — Mww

But the issue is the relationship between what is possible and what is actual, and the fact that one is not a special case of the other, such that the actual would be one of the possible. What we believe as "actual", is what is, of necessity, and therefore not one of the possible. But being not one of the possible in no way implies that the actual, or necessary, is impossible.

As a temporal sort of modality, that seems fine. Once I have marked a box, would either of you say that it is true of each of the other boxes that, though it is not the box I marked, it might have been the one that I marked? If actuality is the closing off possible futures, can we not imaginatively consider an early time at which the actual present was only a possible future, one among many? — Srap Tasmaner

I think this is the common misconception of free will, which leads to all sorts of problems. After you have marked the box, engaged in the free will act, we cannot, from that temporal perspective, say that you might have marked a different box. From that temporal perspective, after the fact, it is impossible that you might have done otherwise. You did what you did, and at this time it is impossible that it might be otherwise. And this misconception (straw man), that if you had free will, you might have done otherwise, when you really can't because what's done is done. gives fodder to the determinist argument, . However, this does not change the fact that prior to the act you have many choices, and there are many possibilities for boxes which you might mark. So free will is very real from this perspective, despite the fact that you cannot have dome other than what you did. What this indicates, is that the two distinct temporal perspectives, prior to an act, and posterior to an act, are very different perspectives.

Above I spoke hypothetically of having a stack of boxes one of which I intended to mark. How do you conceptualize what we are doing when we reason in this way? Am I talking about a possible future in which I do have a stack of boxes? — Srap Tasmaner

I would say that this is simply imagination. However, I would also say that imagination is closely related to the way that we anticipate the future. The principal difference being that we anticipate the future in a way which is grounded in the reality of the past, so it is a disciplined imagination, but we may allow our free imaginations to escape this grounding in an undisciplined sense.

As I said, the two (possible and actual) are not opposed to each other. But obviously, saying "the book is possibly in my room", is to say something completely different from saying "the book is actually in my room". — Metaphysician Undercover

What you said was:

... since actual is defined as what is, it is a logical conclusion that the possible is non-actual. — Metaphysician Undercover

This is false. That the book is possibly in my room isn't that the book is not actually in my room.

This is false. That the book is possibly in my room isn't that the book isn't actually in my room. — Michael

You are not adhering to the definitions Michael. "Possible" refers to what may or may not be. "Actual" refers to what is and is not. If you say that the book is possibly in your room, then you are saying that it may or may not be in your room. This is logically distinct from saying that it actually is in your room, or actually is not, according to the definitions. Therefore the conclusion I stated is sound.

I have no doubt that there is much common usage which is represented by your examples. People say that if there is a multitude of possibilities as to how many coins are in the jar, one of these possibilities is the actual number. And, people also say that if the book is actually in your room, then that it may or may not be in your room is true. But the issue is, whether speaking like this is correct. And I use "correct" here in the sense of what we ought to do, rather than in the sense of what is common practise. Sometimes habits of common practise are not what we ought to be doing.

As I explained above, this habit you describe is the manifestation of a sort of dishonesty. When you say "the book is possibly in my room", this would be a dishonest statement if you believed that the book is actually in your room. Therefore the belief represented as "the book is possibly in my room" excludes as inconsistent with, the belief represented as "the book is actually in my room", in an honest discussion of whether or not the book is in the room. What "the book is possibly in my room" means is distinct from, and excludes as inconsistent with, what "the book is actually in my room" means.

Furthermore, if in the instance of the coins in the jar, we allow that one of the possibilities is the actual (what is actually the case), then all the others must be designated as impossible. Therefore, it should be very clear to you, that if we allow that one of the possibilities is what is actual, this would negate the status of "possible" from all the others. So to correctly maintain the status of "possible", in an honest way, we must not allow the idea that any one of the possibilities is the actual, thereby maintaining the categorical separation between possible and actual. Allowing the separation to be closed contaminates the idea or concept of "possible", in the minds of each of us, rendering us susceptible to deception through that type of usage which has a dishonest base. (I'm trying to appease Srap by not calling your particular use dishonest, rather saying that this type of usage has a dishonest base).

"Possible" refers to what may or may not be. "Actual" refers to what is and is not. If you say that the book is possibly in your room, then you are saying that it may or may not be in your room. This is logically distinct from saying that it actually is in your room, or actually is not, according to the definitions. Therefore the conclusion I stated is sound. — Metaphysician Undercover

Not it isn't.

There's a difference between saying "possible" doesn't mean "actual" and saying "possible" means "not actual".

You asserted the latter, which is false.

You asserted the latter, which is false. — Michael

You misquoted me. I said "non-actual". I suggest you read my post before replying. Your rapid response indicates a strong probability that you did not allow yourself to understand it.

You misquoted me. I said "non-actual". — Metaphysician Undercover

So what's the difference between "not actual" and "non-actual"? What's the difference between "not human" and "non-human"?

That aside, either if something is possible then it isn't actual or something can be both possible and actual. So which is it?

What we believe as "actual", is what is, of necessity..... — Metaphysician Undercover

1.) considering real objects, and 2.) confining the possible to what may be, and 3.) what may not be and belief both being utterly irrelevant.....

Aristotle says so...that which exists, exists necessarily. That which exists cannot not exist.

.....and therefore not one of the possible. — Metaphysician Undercover

Kant says no....That which exists is in the sum of the possible. The sum of the real, the actual, cannot exceed the sum of the possible, therefore is contained by it.

You’re correct in a way...the actual ascends from the sum of the possible, therefore is contained in the sum of the real. Even if the particular real is no longer listed in the merely possible, it remains a member of the modal class of logical categories. It just switches over to the necessary.

The schema of necessity is existence in all time, the schema of possibility is existence in any time, the schema of the real is existence in a determined time.

You know....for clarity.

So what's the difference between "not actual" and "non-actual"? — Michael

That is explained in the post. Iif you will take the time to read it, you can ask me what you do not understand. Depending on what you mean by "not actual", "possible" does mean "not actual". This is because the two concepts are mutually exclusive, inconsistent with one another, such that if something is truthfully said to be possible, it cannot at the same time be truthfully said to be actual. That's what I explained to say one when you believe the other, is to be dishonest.

That aside, either if something is possible then it isn't actual or something can be both possible and actual. So which is it? — Michael

The former, as I explained, and described how this is a logical conclusion derived from the definitions. You can go back and read the posts if you want to understand why this is necessarily the case.

Kant says no....That which exists is in the sum of the possible. The sum of the real, the actual, cannot exceed the sum of the possible, therefore is contained by it. — Mww

The idea that the possible can be summed can be shown to be incoherent, because the possible can be assumed to be infinite. So it is also incoherent to say "that which exists is the sum of the possible", or to speak about "the sum of the possible" in any way.

Having said that, the actual, as we know it, is definitely contained, and it may be the case that it is contained by the possible. But if there is a limit to the possible (a sum of the possible), then the limiting thing must be some sort of actuality. This is a sort of version of Aristotle's cosmological argument, where he demonstrates that in an absolute sense, the actual must be prior in time to the possible. It just isn't the same sort of actuality which is known to us, as this sort is contingent actualities, and these are preceded in time by the necessary possibility. It's a special type of actuality known by theologians.

Depending on what you mean by "not actual", "possible" does mean "not actual". This is because the two concepts are mutually exclusive, inconsistent with one another, such that if something is truthfully said to be possible, it cannot at the same time be truthfully said to be actual. — Metaphysician Undercover

This says {x: x is possible} is a subset of {x: x is not actual}. What's in the rest? What is neither possible nor actual? (Asking for a friend.)

I don't know, to be honest. We always describe things through terms of actuality, what a thing is. So possibility, being not actual, must be something other than this, something which does not submit to description. I believe this makes it impossible to say what "possible" is a subset of, because that would be assigning it some sort of actuality. Therefore, I believe that "possible" must be understood in ways other than descriptive ways. The best way, I think, is with reference to time. Like I said before, prior to the free will act, the act is a possibility. After the act it is an actuality. So possibility is likely some sort of feature of time. And, since the concept of "time" in the way I spoke of it here, encompasses both possible and actual, then we can say that it is neither possible nor actual, but both.

The idea that the possible can be summed can be shown to be incoherent, because the possible can be assumed to be infinite. — Metaphysician Undercover

What’s incoherent in the successive accumulation of the real? When the accumulation is the content of the possible, the quantity is irrelevant. It is whatever it is.

incoherent to say "that which exists is the sum of the possible" — Metaphysician Undercover

Agreed. That in quotation marks and taken from my comment, indicates I said it. But I didn’t. I said that which exists is in the sum of the possible.
————

Aristotle (...) demonstrates that in an absolute sense, the actual must be prior in time to the possible. — Metaphysician Undercover

Agreed. The entire human system of experience is predicated on perception, which makes the real temporally antecedent to the experience of it.

It just isn't the same sort of actuality which is known to us — Metaphysician Undercover

Agreed. The real of perception isn’t known at all, insofar as that real thing, whatever it may be, has yet to be subjected to the system that determines how it is to be known.

this sort is contingent actualities — Metaphysician Undercover

Yes, it is merely a given real something, and is contingent on the system for its identity.

It's a special type of actuality known by theologians. — Metaphysician Undercover

Aristotle restricted it to theologians, but since then, it’s been opened up to every human subject, in accordance with a specific metaphysical theory. On the other hand....what was a theologian for Aristotle, compared to a theologian for us? If the concept changed over time, then probably the applicability changed along with it. Dunno......

What’s incoherent in the successive accumulation of the real? When the accumulation is the content of the possible, the quantity is irrelevant. It is whatever it is. — Mww

When you are talking about "the sum", quantity is not irrelevant. And, a successive accumulation without end, does not produce a sum.

Agreed. That in quotation marks and taken from my comment, indicates I said it. But I didn’t. I said that which exists is in the sum of the possible. — Mww

Sorry, my mistake. Regardless, it is "the sum of the possible" which is incoherent.

This thread's going swimmingly.

So possibility is likely some sort of feature of time. — Metaphysician Undercover

A lot of what we want to say using the alethic modalities clearly does have to do with time, and we do readily make these identifications, future = possible, present = actual, past = necessary. But to say that the future is as yet undetermined, for instance, or that we cannot change the past, if those are to be substantive claims, have to mean something besides the future is future and the past is past. What underwrites that understanding of the temporal modalities?

I think we can say more, and the way to say more is to turn to mathematics, from which time has been deliberately excluded. See what you still have without time. What we find is that there are ways to make issues we are familiar with most often in temporal terms tractable for reason in non-temporal terms.

...there is no opposite to may or may not be. — Metaphysician Undercover

I would have thought the opposite to "may or may not be" was "must or must not be".

If what is actual is not (also) what is possible, then what is actual is (also) what is necessary.

If what is actual is (also) what is necessary, then this precludes free will.

This is because the two concepts are mutually exclusive, inconsistent with one another, such that if something is truthfully said to be possible, it cannot at the same time be truthfully said to be actual. That's what I explained to say one when you believe the other, is to be dishonest. — Metaphysician Undercover

The former, as I explained — Metaphysician Undercover

So you're saying that if the book is possibly in my room then it isn't actually in my room, and so if I tell you that the book is possibly in my room then you know to not look in my room.

Clearly this is opposed to common use.

But to say that the future is as yet undetermined, for instance, or that we cannot change the past, if those are to be substantive claims, have to mean something besides the future is future and the past is past. What underwrites that understanding of the temporal modalities? — Srap Tasmaner

I think what underwrites these modalities is experience. But it isn't direct experience, like we tend to say that sensation is experience, it's more like an analysis of what constitutes experience. This is a philosophical approach to experience. So it is a philosophical activity of the human being, which reflects on its own living experience, recognizing that experience is complex rather than simple, and seeing the need to break it down into its constituent parts.

I think we can say more, and the way to say more is to turn to mathematics, from which time has been deliberately excluded. See what you still have without time. What we find is that there are ways to make issues we are familiar with most often in temporal terms tractable for reason in non-temporal terms. — Srap Tasmaner

To simplify the complex by ignoring the difference between the distinct parts which make it complex, is to produce misunderstanding.

I would have thought the opposite to "may or may not be" was "must or must not be". — Luke

I don't' think this would be a proper expression. I believe it is very similar to the mistake which Michael was making, when you try to oppose possible with necessary. The problem is that when we turn to the temporal nature of reality, what is, is what is necessary. And what is, is in the same category as what is not, as its opposite. Now we would have two very distinct opposites of "necessary", what is possible, and what is not.

So if we accept your proposition, "necessary" becomes very ambiguous. There is the "necessary" which is opposed to "what is not", related to empirical description, and there is the "necessary" which is opposed to "possible", related by your definition, as a proposition for logical proceedings. These two senses of "necessary" are very different, yet very difficult to distinguish.

The issue is that opposites are members of the same category, hot and cold, big and small, positive and negative, etc.. But in a philosophical examination of reality, we find that we need to allow for the reality of things which have no opposite. These are the categories themselves, heat, and size, for example. They have no opposite. And, we've come to know, through experience, that the categories provide the potential (possibility) for actual description. They've been given this name.

But even in the description I just provided, "possible" might be understood as a further category, the category of categories. But this type of description is how the problem of sophistry which Socrates and Plato exposed arises. If we understand this as a category of categories, then this category of categories must be the same as the other categories, being a itself category. Then we want to make sure it is like the other categories, for the purpose of deductive logic, and we represent it as consisting of opposing extremes for the purpose of description. The category of categories is then a category. But it's unsound.

So you would propose that we oppose "what may or may not be" with "what must or must not be", thereby opposing "possible" with "necessary", so that we have an unsound category of "the possible" allowing the possible to be described for the purpose of deductive logic. But all this does is defeat the purpose of putting "possible" outside the categories of logic, thus rendering the reality of possibility impossible to understand through this faulty definition. At the same time, you produce a fictitious, or completely imaginary conception of "the possible", which is totally misleading.

If what is actual is not (also) what is possible, then what is actual is (also) what is necessary.

If what is actual is (also) what is necessary, then this precludes free will. — Luke

Yes, this is exactly the problem with defining "possible" like you propose, which I explain above. It renders "necessary" as extremely ambiguous and misleading.

Clearly this is opposed to common use. — Michael

To the contrary, it is exactly consistent with honest use. When you say that the book is possibly in your room, you imply that the book may be elsewhere. When you say that the book is actually in your room, you imply that it is not elsewhere. So when you say that it is possibly in your room I must decide whether to look there or elsewhere. or how long I should spend searching your room, etc.. But when you say it is actually in your room, no such decisions are required.

This is why it would be deception for you to say that the book is possibly in your room when you believed that it is actually in your room. These two beliefs are inconsistent with each other. So you would be misleading me by telling me something inconsistent with what you honestly believed. Therefore if you continue to insist that this is common usage, I will insist that you commonly deceive.

This thread's going swimmingly. — Banno

Said Pilate who wouldn't stay for the answer. Come on, jump in! Or is it a little too frigid for you?

When you say that the book is possibly in your room, you imply that the book may be elsewhere. — Metaphysician Undercover

But I'm not implying that the book isn't actually in my room.

Regardless, it is "the sum of the possible" which is incoherent. — Metaphysician Undercover

Ehhhhh.....I don’t have a problem with it. The notion of adding to the totality of the possible is quite absurd, from which I can deduce the sum of the possible is given.

The problem is that when we turn to the temporal nature of reality, what is, is what is necessary. — Metaphysician Undercover

Right. That's the problem I'm pointing out to you, which results from your claim that what is actual is not also what is possible.

And what is, is in the same category as what is not, as its opposite. Now we would have two very distinct opposites of "necessary", what is possible, and what is not. — Metaphysician Undercover

I never claimed that "necessary" is the opposite of what is not.

I could equally say that we have two very distinct opposites of "possible" with your claim: what is impossible and what is. However, if I recall correctly, you made the absurd claim earlier that "possible" is not the opposite of "impossible".

Yes, this is exactly the problem with defining "possible" like you propose, which I explain above. It renders "necessary" as extremely ambiguous and misleading. — Metaphysician Undercover

Then you have likewise rendered "possible" as extremely ambiguous and misleading.

But I'm not implying that the book isn't actually in my room. — Michael

What you don't seem to understand MIchael, is that whether or not the book is actually in your room is completely irrelevant here. These statements have nothing to do with whether or not the book is actually in your room, because you could be lying, mistaken, creating a fiction, whatever. The statement refers to what you think, what you believe. And, by stating that the book is possibly in your room, you are implying that you do not believe that the book is actually in your room. "The book is possibly in my room" represents a belief distinct from that represented by "the book is actually in my room. And the one is inconsistent with the other.

If you honestly state that the book is possibly in your room, you imply that you do not honestly believe that it is actually in your room. Therefore your statement "the book is possibly in my room", implies that you do not think that the book is actually in your room. If you belief that the book is actually in your room, and you state that it is possibly in your room, you are being dishonest in your statement. Whether or not the book is actually in the room, or possibly in the room (whatever that might mean independent of belief), is completely irrelevant, so there is no point for you to keep bringing this up. It's just a distraction. We need to focus on the beliefs represented by the statements.

However, if I recall correctly, you made the absurd claim earlier that "possible" is not the opposite of "impossible". — Luke

That's right, imposible ought not be considered as opposite to possible, because it leads to the ambiguity of "necessary" which I described and you don't seem to understand.

Then you have likewise rendered "possible" as extremely ambiguous and misleading. — Luke

Yes, "possible" is extremely ambiguous and misleading. But it has been this way for a long time, so it is not I who has rendered it thus.

When you say that the book is possibly in your room, you imply that the book may be elsewhere.
— Metaphysician Undercover

But I'm not implying that the book isn't actually in my room. — Michael

It's a conversational implicature, that's all. To say "It might be in my room" suggests that you don't know where it is. A good paraphrase is "The book is, for all I know, in my room." This is an epistemic modality, and all it says is that the book being in your room is consistent with your total knowledge. Obviously if you know it's in your room, its being there is consistent with what you know! And that's the thing about the implicature: it suggests that you don't know, but your knowing doesn't make what you said false.

But we don't have to be talking about what people know, what they say, what's implied by what they say, and all that. None of that is implied or relevant if the modality is alethic. Considering only physics and geometry, for example, we might say truly that it is possible for any normal-sized book to be in your room, including this one, and impossible for any normal-sized (non-toy) semi-truck to be in your room. There's reliance here on what we know about physics and geometry, but no one's knowledge of the location any book or truck is in play.

It wouldn't hurt to distinguish the epistemic and alethic modalities now and then.