
Belief Reasoning with Subjective Logic - nathanrosquist
https://folk.uio.no/josang/sl/
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davidwihl
I'm surprised that E.T. Jaynes Probability Theory, nor Ploya's Mathematics and
Plausible Reasoning is mentioned at all in this book, even in the references.

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danielam
Jaynes and Rescher et al. were the first to pop into my mind. Prima facie,
sounds like some kind of epistemic logic with probabilities.

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blueprint
So close, but just misses the mark.

This statement contradicts itself:

> We can assume that an objective reality exists, as "das Ding an sich" (the-
> thing-in-itself) in the pholisophy of Kant, but our perception of that
> reality will always be subjective.

in that the latter clause is an objective statement about perception
necessarily, by its assumption, derived through said limited subjective means.

"Do not rely on your thinking in order to know the world"

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danielam
Yes, I read that passage and was left irritated by the philosophical
mediocrity of it. Name-dropping Kant only makes matters worse given that his
conceptualism is incoherent.

The subjective/objective distinction is problematic. Obviously, knowing agents
are always subjects -- something has to be doing the knowing -- but knowledge
of that presupposes that the subject is able to know the world as it is in the
first place.

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blueprint
All subjects exist in their environment. Their own individual truths are
unique just as they are.

Suppose you look through a bucket of polluted water. It's difficult to see
through it. Heck, it's difficult to tell what's even IN the bucket because the
water is murky. If the water is clean, and you shine a light into it, then,
things in it are visible.

The analogy is to the degree of truthfulness of an individual's consciousness.
The higher the truthfulness, the higher the degree of precision with which
they can make confirmations about what exists as it is.

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bovermyer
On the face of it, this phrase seems dissonant to me:

> However, in the long term it's detrimental to the stability of global
> civilisation when we hold and promote different and conflicting subjective
> truths.

If it's referring to "subjective truths" as identity beliefs, then yes, it
could be an accurate statement. But if "subjective truths" is referring to
more malleable beliefs decoupled from identity, then I'd say it's overstating
things. Conflict that can be resolved with a positive outcome for all involved
is better than no conflict, as a lack of conflict can lead to stagnation.

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YeGoblynQueenne
I think the point is that there are some opinions that must be based on
objective truth (whatever that is), for civilisation to remain stable. For
instance- accepting the fact that our activities are causing climate change is
something that has the ability to affect our chance of survival as a species
-etc.

I don't think the author means that _every_ belief held by any person must
ultimately become "objective" (and, therefore, aligned with that of all the
rest of humanity). For instance, I don't see how it is bad for human
civilisation if I think I look ravishing in red, whereas everyone else thinks
I look like a pillock.

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ThomPete
They can appear to be objective, they cant ever be actually objective in any
universal way. There cannot be a correct interpretation of reality in any
logical system as all premises are fundamentally impossible to validate.

Luckily we dont need to know whether something is objectively true for it to
be useful. And useful is really all you need.

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mhale
The wikipedia page on Subjective Logic goes into more detail:
[https://en.wikipedia.org/wiki/Subjective_logic](https://en.wikipedia.org/wiki/Subjective_logic)

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hliyan
Is this in any way a variation on fuzzy logic? I learned it on University 15
years ago, saw some applications in some cameras, never to be seen again.

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andromeduschill
Could someone highlight a few applications of this?

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matt4077
It's an explicit formulation of a process that you, and everyone else, follow
all the time.

You might, for example, trust your spouse. You have no problem giving them
your car keys, because you believe they are unlikely to steal the car.

Now a stranger asks you to borrow your car. You would probably not give them
the keys.

But then you learn that the stranger is a good friend of your spouse. Because
you trust your spouse, and they trust their friend, your trust in the stranger
just grew, and you would probably consider giving them the car.

Using many such chains, with some discounting as the length increases, you
could, for example, create a trust score for a news story.

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indubitable
In my opinion, this possible application would be rather counter productive as
social trust at any scale is generally based on little more than marketing and
public relations. Most would now say Harvey Weinstein is one of the most
despicable people in this country - and his behavior was an open secret. Yet
if you did any sort of networking trust mechanism just last year, he would
have ranked near the top. And this is assuming we could perfectly measure such
things. In reality that measurements, and measurers, are themselves rife with
potential issues. And any measurement would be completely gamed.

Fundamentally, this would seem to do little more than work to entrench already
established forces who would tend to the score the highest, or equivalently
have the resources to the game the system most effectively.

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pault
Meta: it's curious that this green account created two hours ago only has two
submissions, both of which reached the top 10 on the front page.

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platz
Jealous of the unicorn points?

