On Thursday, November 14, 2019 at 8:15:18 PM UTC-7, Brent wrote:
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> On 11/14/2019 6:30 PM, Alan Grayson wrote:
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> On Thursday, November 14, 2019 at 7:18:02 PM UTC-7, Brent wrote:
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>> On 11/14/2019 5:48 PM, Alan Grayson wrote:
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>> On Thursday, November 14, 2019 at 5:34:02 PM UTC-7, Brent wrote:
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>>> On 11/14/2019 4:20 PM, Alan Grayson wrote:
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>>> Newton is considered superior, not just because his theory was more
>>>> accurate, but because it had a universal application. The greatest
>>>> importance of Newton was that he broke the idea that the heavens went by
>>>> different rules than the Earth. So "truth" per se is not the distinction.
>>>>
>>>> As Bill can tell you astronomers have no problem with regarding the Earth
>>>> as stationary and the Sun going around it. But they use Newton's
>>>> equations
>>>> to determine how it goes. It's convenience...not truth.
>>>>
>>>
>>> Bill's failing, as I recall, was the belief and insistence that he's
>>> always right. No astronomer of sound mind would regard the Earth as
>>> stationary and the Sun going around it. AG
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>>>
>>> Not at all. They do it all the time, because when it comes to aiming
>>> your telescope you do it relative to the Earth, not the Sun.
>>>
>>> Brent
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>> I was thinking of calculating the orbit of a planet. For stars apparently
>> fixed on the celestial sphere, Earth centered calculations are convenient.
>> AG
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>> Which is the point. There is no "true" center of the solar system, there
>> are just more and less convenient coordinate systems in which to calculate
>> things. So you need to ask yourself what do you mean when you say it is
>> more true that the Sun is the center of the solar system and the Earth
>> orbits the Sun than the other way around? If you're honest you will
>> conclude that you mean it is easier to make good estimates of the future in
>> that coordinate system. Why is Einstein's gravity "truer" than Newton's.
>> Why is the quantum atom better than the Bohr atom? Why is Darwinian theory
>> better than Lamarckian. The reason one scientific theory is better than
>> another is three dimensional:
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>> 1. It gives more accurate predictions where the theories overlap and no
>> emprically false ones.
>> 2. It has a wider domain of application. It applies in more places or
>> over a bigger range of parameters.
>> 3. It is consilient with our other best theories. So it reduces the
>> number of different things we must understand as independent.
>>
>> A theory that is better on all three dimensions, we regard as truer.
>> Not the other way around: It is not the case that we judge it better
>> because it's truer, because we don't, and can't, know where the truth is.
>>
>> Brent
>>
>
> So when we see ~200 billion stars rotating around the galactic enter, it's
> equally true that each star can be regarded as the center, with everything
> rotating about itself.
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> Sure.
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I meant to put a question mark at the end of that sentence. AG
> You know there's no 'center of the universe' in any current model.
>
To the extent that galaxies rotate, they have a center. AG
For such a center to have any operational meaning would require that
> momentum not be conserved.
>
> This is a form of relativity, let's call it the relativity of truth, that
> find obscures the value of evolving models in better describing the
> external world. AG
>
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> Except that still invites looking at it backwards; as though there is
> something called "the truth" but it's relative to what we know. I'm saying
> that there is a concept of "truer" that has an operational meaning, but
> there is no operational meaning to "the truth" that we are approximating.
> The only meaning I can give "the truth" is the collection of propositions
> expressing the known empirical facts; but even those are ambiguous because
> every observation depends on some theories.
>
> I've explicitly described how we define models as better ("truer") when we
> evolve them. Do you have some other criterion? Something involving what's
> true?
>
> Brent
>
There's a philosophical principle that I endorse; namely, that there exists
an external world and hopefully our models are increasingly better
descriptions of that world. At least that's our goal. Beneath your words
seems to be a denial of that principle. We can call this "the truth",
although I don't think I used that phrase. AG
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