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12:13 AM
@Espinoza @HerrWarum Hi
 
hello @LastIronStar
 
What brings you to Logic today?
 
i'm still trying to figure out how chat on mse works, just clicked on different chat rooms
 
Ah cool
This room is primarily used to discuss Mathematical Logics, if you have any question on Logic feel free to ask, someone should be here shortly(more knowledgable than me) who will try to answer your questions! Nevertheless, I may attempt a discussion on the same :)
@HerrWarum ^
 
cool, thanks
 
 
2 hours later…
2:09 AM
@user21820 transfinite induction and ZFC as a whole are meaningful and sound beyond possible reproach
@user21820 There is no possible universe in which a sane person could possibly differ
 
 
1 hour later…
3:32 AM
@user21820 Also, Boolos: "Thus a Godel sentence 'says of itself' that it is unprovable..."
 
user131753
3:47 AM
@user21820: Do you know of any formal system that has a real meaning but has no model?
 
user131753
@DavidReed: Have you gone through all the links that were suggested as a reference to your question "Was Mathematics invented or discovered?" in the Philosophy of Mathematics chat room?
 
@user170039 Hey! How are you?
 
user131753
@DavidReed Have you?
 
I have not yet, I had that was a starred comment
i didn't know that there was a link there
ill check it out now
 
 
1 hour later…
5:04 AM
@DavidReed That doesn't make any sense. ZFC is meaningless and almost all the set theorists agree with me on that.
@user170039 What does "model" mean?
 
@user21820 yah you're probably right
oh well
 
Lol.
Were you trying to pull my leg?
 
My goal was to evoke an emotional response from you
 
@DavidReed Aww.. Too bad I saw through it and gave you a half-hearted factual response.
 
I think I would up instead upsetting 0039
 
5:09 AM
@user170039: I should add that for set theorists who believe that the set theoretic universe somehow exists (even though meaningless in the real world) they believe that ZFC has a second-order 'model', which of course is too big to be a model in the usual sense as defined in ZFC itself.
This viewpoint can be seen in various posts, but I'm a bit lazy to find them since I'm sure you can. Just search for "second-order ZFC".
=)
@DavidReed: Anyway do you like abstract games and puzzles?
@LastIronStar Now here yes.
 
You sent me some last night
 
Yea; do you like such abstract recreations in general?
 
Maybe
 
So what do you do in your free time, besides reading books? =)
 
Your definition of abstract recreation is too abstract for me
When I'm in my current state tends to be more social activities and less introspective stuff
Come mid Jan there will be a 180
I'll likely finish working on the radio i was designing
Dive into noethers theorem
And study for classwork
And most
I hate this kindle autocorrect it is ruining my life
Anyways, I'm going to guess that I would like it
?
 
5:35 AM
@user21820 Wanted to say I'm not convinced that there is a logical argument for existence of Supreme being and that there is one refuting we are our bodies. However I see you finished the conversation I started yesterday, maybe some other time we discuss it!
@user21820 How many times has the sun gone around you?
 
@LastIronStar Well it's okay to be not convinced. I'm not vested in convincing anyone. But you should think carefully about my reasoning that I linked you to at the beginning that leads to the conclusion of a lawmaker.
Basically, everything as a whole is a sufficient reason for everything, and we wish to look at a minimal part L of everything that is still sufficient reason for everything. L must be a lawmaker because L cannot itself be yet another physical law. And from the stability preserving property of the physical laws it makes sense to infer that they were not instituted arbitrarily, and hence L must have had some intent behind them.
(To me at least.)
@LastIronStar Matters of perspective do not matter because I am referring to matters of absolute truth, and not statements whose meaning changes from context to context. =)
@DavidReed What is a 180?
 
@user21820 you said roughly a decade, i asked cos of that
 
@LastIronStar What a round about way of asking my age lol...
Not telling!
=P
 
180 degree turn. That is, day 2 day liftestyle will change drastically
 
Oh I see.
 
5:43 AM
lol
 
I finished undergraduate studies some years back.
You?
 
@user21820 I'm doing my Graduate Studies.
 
@LastIronStar Same then.
 
@user21820 probably not I think :P
@user21820 Your main argument yesterday was about refuting the certainty that evolutionists presume is valid.
 
there is no such that as certainty in science
only evidence
in terms of evidence, evolution ranks very high on the list
no such thing*
 
5:48 AM
@user21820 moreover, a logical argument means that the conclusion is inevitable for anyone willing to follow through the argument as long as they agree on your assumptions.
 
another word for that is a cogent argument
 
Are you saying cogent is different from logical?
Is it a difference of semantics vs syntactic again lol?
 
I'm saying that in the field o persuasion, a cogent argument is defined to be a valid argument having all true premises
 
Ok
thank you
 
I wasn't intending to be abrasive
 
5:50 AM
@LastIronStar At the start I linked to a philosophical argument that I just summarized. I did not describe it at all yesterday.
 
No you were not @DavidReed
 
@LastIronStar I meant I'm also doing graduate studies.
 
good :)
 
@user21820 OK
 
@LastIronStar Of course, and my argument I just summarized is actually logical even if you don't accept my premises (which I didn't really state). =)
Oh by the way, science is also based on a slight assumption of some form of free will, because for falsification of a hypothesis to be possible we have to assume we can in fact run experiments on arbitrary inputs so that we can obtain statistical data.
This is a much weaker form of free will (some may not consider it free) than the one I believe in though.
But just something to ponder.
 
5:55 AM
@user21820 I probably should nail down the difference between cogent and logical in my head. One keeps popping up when the other is what is needed. Now i'm confunded as to whether I believe there is not a cogent argument or a logical argument. I think it is not possible to use perception and inference to establish Supreme being. So I believe that Logical Argument is itself not possible then!
Ofc, I've not refuted your logic, which granted you will probably have to wait a bit longer for if you are interested to know.
 
@LastIronStar Well if you a priori assume that logic cannot achieve something, then you of course have restricted yourself to be unable to do so (or at least unable to consistently do so).
Anyway I said before that any argument involving the real world is not going to be capturable 100% syntactically.
Because it refers to semantic notions.
 
@user21820 It's not apriori, I have had to construct counters to logical arguments for SB before this, so this one i'll have to construct one too. Just not constructed yet.
I know i'm inducting, but still...
 
Consider "Something exists." which is clearly true (self-justifying). You don't doubt this, right?
 
@user21820 You can have this for free: We are not our bodies.
 
we are linked to our bodies though
we are an emergent property of efferent neural activitity
 
6:01 AM
@LastIronStar Actually I didn't get your this remark the last time either. If you are saying that the physical world is not everything, then it is already an unscientific (and empirically unfalsifiable) statement, so why is it so strange that I also invoke philosophical arguments that go beyond the physical world to infer that there is a lawmaker that is beyond the physical world?
 
@user21820 I claim that using logic (perception and inference) it is possible to make my claim. So it is not unscientific but rather a tautology(am i using it right?)
 
No your last sentence does not make any sense. Perhaps you typed wrongly.
 
@DavidReed Can you explain the difference between a corpse and a being that is online so to speak?
@user21820 I am saying it is a logical argument because you can use inference and/or use perception to justify it.
 
Is this a Descartes question?
 
@LastIronStar David would probably disagree with you, I think.
If however you hold that you are purely a result of biochemistry and social interactions and your physical environment, like David seems to, then you are essentially saying there is no such thing as free will. But then you have to think again about your assumptions regarding scientific experiments.
 
6:05 AM
was afk so not sure whats happening
 
@user21820 No I'm saying we are something that is embodied. Not the body itself. and that the embodiment cannot create or destroy that something's existence.
 
i would definitely disagree with that
 
@LastIronStar: If on the other hand you hold that you are not purely physical, then you cannot a priori dismiss my philosophical argument as invalid just because it invokes reasoning about things beyond the physical world. The concept "everything" is not something that you can perceive or infer from perceptions.
 
the embodiment creates the conscious entity known to you as 'david" Reed
As evidence I cite the way we can make changes in the mind by making changes in the body
 
@user21820 I agree, I'm saying that a logical argument is not possible that's all, a cogent argument is possible perhaps.
 
6:08 AM
@DavidReed That is only evidence that you are partly influenced by the physical world.
 
Let me make myself clearer
 
@DavidReed So? Even a novel can make changes to my mind if I read it.
 
@LastIronStar Well that's a matter of perspective then. Any cogent argument can be represented by a logical argument, by translating it into some suitable language. There is still the semantic gap to go from the translation to the intended semantics, but it can be considered logical.
 
If I came to your house 820, and injected you with IV sinimet, you would lose your sanity. You would completely lose your grasp with this world
If I injected you with diprovan you would cease to exist for about 15 min
 
@user21820 I don't follow
 
6:10 AM
After all, if you take any simple number theory fact like Fermat's little theorem, it is just a symbolic string. We use it in practical real world applications like RSA by interpreting its intended semantics.
And it has worked well.
 
@DavidReed admittedly I have not read anything this good. But the argument holds.
 
If I severed your corpus callosum you would cease to be one person and become two
I'm not even sure what argument we are talking about
 
@LastIronStar: Similarly, I could write my argument in some formal system by appropriate use of symbols to represent the entities and concepts I am referring to, and you can very well disagree with the semantics I wish to imbue them with. But the argument itself can be logical; just that we may disagree on whether it means anything in the real world.
 
@user21820 Ok, what is the formal argument here?
 
So when I said "logical" I meant that the argument has a relatively clear logical structure, so all that is left is for you to analyze its assumptions.
 
6:12 AM
@DavidReed There's two going on right now :)
 
@LastIronStar The base assumption is that everything has a reason, which is captured by a conceptual category, which may contain more than one entity.
Thus the conceptual category "everything" has a reason, but the reason itself is part of everything. So we conclude that "everything" as a whole is a reason for "everything".
But that's not what I'm after. I wish to get to a minimal reason for "everything".
And by suitable assumptions, I can conceive of and define L to be such a minimal reason.
And then you look at the physical laws, which must too have a reason.
That reason cannot be part of the laws, because a law needs something to institute and enforce it. This again is some further assumptions. You can represent it via axioms if you wish.
Thus L is beyond the physical laws, in the sense of not being contained by the physical laws alone.
I just call L lawmaker because it's a fitting word, but you can stick to L.
Then you go on and reason about the reason for the way the laws are.
Of so many possible choices of consistent laws, this particular collection was instituted, and there must be a reason. This reason resides in L.
L has intent, and that intent must be consistent with the nature of the laws, which appear to us to be stability preserving.
Hence I infer that L's intent includes stability preserving.
Can an unconscious entity institute highly stability preserving laws? Well, of course anything consistent is possible... But unlikely (in my information theoretic sense).
 
@user21820 Why is reason necessary? You are saying that there needs to be a reason(which if i'm not wrong is to be understood as the perceptive and inferential faculties we possess)
 
@LastIronStar Reason does not mean the kind of reasons humans have.
And I said that it is an assumption.
Every formal system will have at least one assumption otherwise there is nothing you can prove besides semantics-void tautologies.
Even PA has infinitely many axioms.
 
@user21820 you are right, but I asked because the reasoning used to make your case and the reason you assumed seemed to be the same from my reading.
 
Sorry it is unfortunate that English has "reason" with two different semantics.
 
6:21 AM
poor choice of words perhaps
 
By "has a reason" I mean "has something that entails it", more or less.
I can't express it much better in this limited human language...
 
@user21820 Can I say everything has a cause?
 
@LastIronStar My axiom is that everything has a reason, but not necessarily a cause in the usual 'causality sense'.
 
in other words
your axiom says absolutely nothing at all
 
@user21820 Ok, so is it right of me to think that a logical argument requires us to understand what the assumption is in order to establish whether it is logical or not?
 
6:24 AM
@DavidReed No. Entailment is not nothing.
@LastIronStar Well that's why I made more explicit where the assumptions are.
 
I've read now what your axiom is, and I still have no idea what it says
 
@user21820 I don't understand your assumptions
 
Why not. You definitely assume this axiom in everyday life. When you encounter something, you expect that there is some reason behind it even if you cannot figure it out. That reason may be random fluctuations in some things, or it may be conscious intent by someone else, or something else.
The axiom merely says that it applies to everything, not just things in your daily life.
 
Its too ambiguous in its language to me for me to accept it as an axiom
 
Of course it is ambiguous. This is natural language. How else do you want me to say it? In some first-order language?
 
6:29 AM
@user21820 So reason means something that can be categorised into material, instrumental, efficient? Is this correct?
 
I guess my answer would depend on what you intend to prove with it
 
@user21820 I don't know how this reason is different from the normal reason being used.
 
@LastIronStar I'm not sure what "efficient" here means. But generally most reasons are causal, and some others are of necessity rather than causal. I'm using the meaning of "reason" exactly as one of the dictionary definitions of it in English:
> c. A fact or cause that explains why something exists or has occurred
 
8 mins ago, by user21820
@LastIronStar My axiom is that everything has a reason, but not necessarily a cause in the usual 'causality sense'.
 
Exactly.
A fact or cause.
The confusion arose because earlier I also used the word "reason" to refer to my reasoning, which is a different definition:
> a. The basis or motive for an action, decision, or conviction
 
6:32 AM
For every event, there is a fact that explains it
am I warm or cold there
 
@DavidReed Yes. But here I was a bit more precise and say that a reason can be a conceptual category. So many different categories could be reason for the same thing. It is more like a relation.
And I am interested generally in the minimal reason for things.
Which you too are, on a daily basis.
 
I would do my best to avoid taking that as an axiom
that's just my own personal taste though
It's too big for me to swallow
 
Ok, so you are saying that there is some underlying "fact" that explains existence of everything - Is this your axiom?
 
If you see your phone broken, you immediately infer that there is a minimal reason for it. You do not tell yourself that the universe or some big bunch of random facts is the reason for it. You instead guess that someone or something did it to your phone via a direct physical interaction.
 
what entails an explanation? Are they formed from the same logical apparatus we use or can be something else?
 
6:37 AM
@LastIronStar I don't get your question?
Are you asking for what can be reason for explanations?
 
@user21820 I'm talking about "A fact that 'explains' why something exists or has occurred" definition
 
@LastIronStar That is what is written in a dictionary for the populace.
There is an underlying meaning it is attempting to capture, so reading too much into the surface phrasing is not going to be helpful.
 
@user21820 But you said, "I'm using the meaning of "reason" exactly as one of the dictionary definitions of it in English"
 
I think that precise people do use the word exactly as I am using it. But the dictionary definition may not capture that!
That's why I even gave my own earlier:
18 mins ago, by user21820
By "has a reason" I mean "has something that entails it", more or less.
You could think of it as modal necessity of the reason implying necessity of the result.
 
OK, I'm not following your last sentence... Is modal important there?
 
6:44 AM
No. It's just that in logic we represent necessity via modal operators.
@DavidReed: By the way, in my opinion anyone who rejects this axiom that everything has a reason essentially does not want to address the question of why the world is the way it is. To see why, consider that our best guess is that the big bang started this universe. Where did the big bang itself come from? If you say it just arose, you're evading the issue. If you say there were previous cycles, then why are there cycles in the first place? What governs those cycles? And so on.
 
@user21820 Then, it is best we pause our discussion at this point, do you agree to that?
 
@LastIronStar I have no problem with pausing, though I don't see how it is related to the notion of necessity.
 
@user21820 We can unpause when these technical terms have been naturally learnt - that's what i meant
 
Oh sure.
We should anyway get back to logic, where things are clear-cut yes/no.
=)
 
@user21820 Ok, well admittedly i am very tired, and have been in and out of the conversation. I should be able to give it a more alert look tomorrow. I'm off to bed for now though. Will see you guys soon.
 
6:48 AM
@DavidReed Good night and rest well! =)
 
I agree, coming up with proofs are fun lol
@DavidReed GN
@user21820 I will be busy in a bit, perhaps if you find time once you are up we can continue where we left off in Logic studies?
 
Sure. Later perhaps @Secret will also be back and we can continue from where we left off.
 
@user21820 ok cool bye.
 
Bye!
 
 
7 hours later…
1:21 PM
@user21820 you might be interested in this:
 
Hi @LeakyNun @user21820 @Secret
 
inductive true : Prop
| intro : true

inductive false : Prop

inductive eq {α : Sort u} (a : α) : α → Prop
| refl : eq a

structure and (a b : Prop) : Prop :=
intro :: (left : a) (right : b)

inductive or (a b : Prop) : Prop
| inl {} (h : a) : or
| inr {} (h : b) : or
@LastIronStar and you have to interrupt a message
@user21820 ^^ how various things are defined in Lean (type theory)
 
@LeakyNun sorry?
 
@LastIronStar nvm
 
@LeakyNun Are you specialising in Logic in your undergrad?
 
1:27 PM
no
 
I see
You've picked up a lot of Mathematics this young, kudos!
 
2:14 PM
Hello!
@LeakyNun It's slightly too dense for me to get what it is about.
What is "intro" and "refl" and "inl" and "inr"?
 
@user21820 I think the last one is the easiest to understand
oh, they are just names
 
Are you using the type theory kind of notion where a proposition is a type and is true if inhabited?
 
in java: class or { public or(a inl, b inr)}
@user21820 yes
and I dont speak Python OOP
 
@LeakyNun Still doesn't make sense, though I know Java... How can you have a,b as types?
 
so a is a prop
let's say a is 0=1
something of type 0=1 is a proof of 0=1
 
2:19 PM
Yea, but Java does not support using objects as types.
 
that's just a loose analogy
 
Oh.
 
I didn't intend it to be java per se
@user21820 so false has no constructor
it can never be constructed
true has one constructor with no argument
it can always be constructed
 
I get those. It's the other more complex definitions that I don't get.
 
oh, my java code above is wrong
it should be for and
class and { public and(a left, b right){} }
@user21820 which one?
 
2:24 PM
Well I know zero of the syntax of Lean, so obviously the last three don't make any sense to me.
 
right
the last one is the easiest
inductive or (a b : Prop) : Prop
| inl {} (h : a) : or
| inr {} (h : b) : or
or is an inductive type
let's just treat it as a type
it takes two arguments as input
so it's a class of types
i.e. given two Props, return a type
to instantiate something of type or a b, either give a proof of a or give a proof of b
 
How on earth does "(a b : Prop) : Prop" mean what you just wrote?
Oh.
 
it eats two Props and return one Prop
 
The space between "a" and "b" actually means ","
 
yes
 
2:27 PM
Then what is the {} for?
 
ignore it
 
shouldn't there be "or a b" instead of "or" ?
(or is it implicit ?)
 
implied
 
@mercio: Hello and good to see you here!
 
hello
I haven't touched Coq in so long
 
2:28 PM
that's a dialect of Coq called lean
 
@mercio He's saying it's Lean not Coq, and I've touched neither.
 
or treat it as a separate language
 
Oh.
 
but it's similar enough
 
All I know about Coq is that it has a weird type hierarchy.
Heheh..
 
2:29 PM
@user21820 do you get it?
 
I can't tell.
Since you didn't say what the {} is for, I wouldn't know.
 
I'm figuring that out too
 
LOL!
So you don't get it yourself...
 
lol
but do you get the other parts
 
This must be the most amusing thing for me in a week.
 
2:32 PM
maybe it's for implicit type arguments
 
I don't get what "Sort" is doing over in the other one.
 
(i have no idea)
 
And why there is ":=" in another other one.
 
idk there's all kinds of sorts and types and props
i never really caught the subtleties with them
 
@mercio I only briefly looked at the theoretical type theory underlying Coq, and suffice to say it's totally ad-hoc. There were a number of early version that were found inconsistent, so the current system is really a potpourri of random notions that nobody has found an inconsistency in yet. =P
 
2:34 PM
just like I remember, then !
 
Haha! Anyway what brings you here today? =)
 
i haven't slept last night and so I4m a bit unable to do anything so I decided to read a math paper instead
 
Oh.
Do you specialize in logic?
 
@user21820 it works without {}
the {} usually contains the implicit argument
@user21820 do you really have to bash everything
 
@LeakyNun Oh nice. You just got a leaner definition.
 
2:37 PM
not really
 
@LeakyNun I just praised your newfound definition.
 
lol
@user21820 Sort is like a metatype
something of Sort is a type
 
I know that, but apparently I vaguely recall a Prop can quantify over Prop or something like that.
 
if I wrote {α : Type} instead, I wouldn't be able to have (a : α)
inductive eq {α : Sort u} (a : α) : α → Prop
| refl : eq a
 
I know; it's like a 2-order type theory.
 
2:40 PM
@user21820 not sure what you mean
hierarchy:
true.intro : true
true : Prop
Prop : Type
Type : Type 1
Type 1 : Type 2
(true.intro is a proof of true)
 
2:58 PM
@user21820 ah, the {} does have some use
without it, a proof of or a b would have to be or.inl a b (something : a)
with it, I only have to type or.inl (something : a)
so the {} makes a and b implicit
 
Uh..
Never mind.
It's this kind of thing that puts me off from learning how to use existing proof assistants. Even if perhaps to my disadvantage.
 
@user21820 You are correct regarding me not wanting to address why the world is the way it is. Questions for me like "what caused the big bang" are very likely beyond the realm of human intellect, and at the very least beyond mine.
@user21820 I reject the axiom though, although its an implicit assumption in my day to day life as you mentioned, because it is too general and abstract for my personal taste
 
o..o
 
@user21820 :c
 
@DavidReed Alright. No problem. In fact, if you don't already know by now, I do not really care what people believe in, as long as they do not (except in exceptional circumstances) harm others intentionally.
=)
@mercio We were discussing non-logic stuff a while back.
 
3:04 PM
maybe
 
@LeakyNun I do wish there was something more user-friendly.
 
@user21820 Ok, well if I harmed you in some way I'm sorry. I will say I would cheerfully accept it as an axiom for a suitable subclass of events
 
@DavidReed No you haven't harmed me! I'm saying that beliefs are of secondary importance to me than morality, so it's perfectly fine for you to disagree with me strongly on beliefs that do not impinge severely on moral decisions.
 
@user21820 I think it's already user-friendly enough
 
if anything, Coq taught me to be extremely rigorous if i need to in my proofs
 
3:05 PM
@mercio that's nice
 
@mercio Ah that's amazing. I did it by imposing my own Fitch-style system on myself.
But I heard that Coq also might do that to some people.
Though I had classmates who just randomly tried tactics rather than really understand what was going on.
 
@user21820 I do both...
 
Lol!
 
3:18 PM
@user21820 did you receive a ping from main chatroom?
 
@LeakyNun No I didn't. If the username does not show up when you type the @, it means that they will not get pinged (because they were not there recently enough).
@Rick: Hello! What brings you here?
This room is usually logical, but not always.
 
Oh, I was just exploring around
 
@Rick Oh okay. Feel free to explore then!
@LeakyNun The thing I don't like about hanging around in the main chat-room is that it is too noisy. Every now and then there is a new message haha..
 
fair enough
@user21820 aha, I can see my own deleted message, but the public cannot
 
3:40 PM
@LeakyNun What do you mean?
 
@user21820 you can't see what I deleted
 
In chat, all messages that you delete yourself are visible to me.
 
maybe because you're room owner
 
On main, all comments that you delete are invisible to you too.
@LeakyNun No it works in rooms where I am not an owner.
 
:o
 
3:41 PM
Try deleting one of your messages in another room.
 
@user21820 done
 
@LeakyNun That is strange. Last time it was visible to everyone.
 
@user21820 interesting
 
@LeakyNun: Can you see this?
 
:o
yes
 
3:47 PM
@LeakyNun So why can't we see history of chat messages in the main chat-room?
 
no idea
@user21820 I have a program H that takes a program and returns whether it halts on an empty input.
 
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