# Re: Trust in statements (was BioRDF Brainstorming)

From: Matt Williams <matthew.williams@cancer.org.uk>
Date: Wed, 13 Feb 2008 21:08:55 +0000
Message-ID: <47B35C67.2030506@cancer.org.uk>
To: Alan Ruttenberg <alanruttenberg@gmail.com>, public-semweb-lifesci hcls <public-semweb-lifesci@w3.org>
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Dear Alan,

Thank you for making my point much more clearly than I managed. I'm a
little wary of probabilities in situations like the one you describe, as
it always seems a little hard to pin down what is meant by them. At
least with the symbolic approach, you can give a short paragraph saying
what you mean.

I'll try and find a paper on the "p-modals" (possible, probable, etc.)
and ways of combining them tomorrow and put a paragraph on the wiki.

Matt

Alan Ruttenberg wrote:
> I'm personally fond of the symbolic approach - I think it is more direct
> and easier to explain what is meant. It's harder to align people to a
> numerical system, I would think, and also provides a false sense of
> precision. Explanations are easier to understand as well: "2 sources
> thought this probable, and 1 thought is doubtful" can be grokked more
> easily than score: 70%
>
> -Alan
>
> On Feb 12, 2008, at 4:03 PM, Matt Williams wrote:
>
>>
>> Just a quick note that the 'trust' we place in an agent /could/ be
>> described probabilistically, but could also be described logically.
>> I'm assuming that the probabilities that the trust annotations are
>> likely to subjective probabilities (as we're unlikely to have enough
>> data to generate objective probabilities for the degree of trust).
>>
>> If you ask people to annotate with probabilities, the next thing you
>> might want to do is to define a set of common probabilities (10 - 90,
>> in 10% increments, for example).
>>
>> The alternative is that one could annotate a source, or agent, with
>> our degree of belief, chosen from some dictionary of options
>> (probable, possible, doubtful, implausible, etc.).
>>
>> Although there are some formal differences, the two approaches end up
>> as something very similar. There is of course a great deal of work on
>> managing conflicting annotations and levels of belief in the literature.
>>
>> Matt
>>
>> --http://acl.icnet.uk/~mw