Philosophy of science-the first two and a half millennia.

How does science work? And what's all this about quantum mechanics?

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TimeSeeker
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Re: Philosophy of science-the first two and a half millennia.

Post by TimeSeeker » Sun Sep 30, 2018 7:49 pm

surreptitious57 wrote:
Sun Sep 30, 2018 7:31 pm
There cannot be anything outside of ALL THAT EXISTS
So the fact that you are using the words 'inside' and 'outside' - can I assume you think that the 'everything' is 3-dimensional and is contained inside a box? You still haven't explained where all the energy is going if there is no 'outside'.

Also - the words 'inside' and outside' don't really work with multi-dimensional Hilbert spaces.So lets not put the universe in a "box" that it doesn't belong just yet. Can we at least estimate how many dimensions there are? So we can conceptualize the Hilbert space we are talking about?

And I am still perplexed by this 'all that exists' claim. We have the observable universe and then we have the unobservable universe. How is it that you feel so comfortable making claims about the 'unobservable universe' ?

surreptitious57
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Re: Philosophy of science-the first two and a half millennia.

Post by surreptitious57 » Sun Sep 30, 2018 7:58 pm

I do not think everything is three dimensional and inside a box that is too simplistic an interpretation. We observe four dimensional spacetime
but there may be more dimensions at the quantum level we do not experience. The Universe might be infinite but if it is finite then there can
be nothing outside of it. It is currently expanding but not into anything as such. If it is infinite then the concept of outside may be nonsensical

TimeSeeker
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Re: Philosophy of science-the first two and a half millennia.

Post by TimeSeeker » Sun Sep 30, 2018 8:02 pm

surreptitious57 wrote:
Sun Sep 30, 2018 7:58 pm
I do not think everything is three dimensional and inside a box that is too simplistic an interpretation. We observe four dimensional spacetime
but there may be more dimensions at the quantum level we do not experience. The Universe might be infinite but if it is finite then there can
be nothing outside of it. It is currently expanding but not into anything as such. If it is infinite then the concept of outside may be nonsensical
So all that dark matter we can't account for is hiding in which direction ? ;)

And you haven't yet committed as to whether it 'exists' or not.

surreptitious57
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Re: Philosophy of science-the first two and a half millennia.

Post by surreptitious57 » Sun Sep 30, 2018 8:15 pm

Dark matter and dark energy between them account for ninety six per cent of the observable universe
And so they definitely exist but as to what they actually are is a mystery hence the placeholder names

TimeSeeker
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Re: Philosophy of science-the first two and a half millennia.

Post by TimeSeeker » Sun Sep 30, 2018 8:21 pm

surreptitious57 wrote:
Sun Sep 30, 2018 8:15 pm
Dark matter and dark energy between them account for ninety six per cent of the observable universe
And so they definitely exist but as to what they actually are is a mystery hence the placeholder names
Except they aren't placeholders. They are called 'dark' because they aren't... How you say this? Observable.

So something that can't be observed/detected/measured can exist? Good to know ;)

And it accounts for 96% of 'everything'? I'll go ahead and call it God for your convenience.

surreptitious57
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Re: Philosophy of science-the first two and a half millennia.

Post by surreptitious57 » Sun Sep 30, 2018 9:26 pm

Dark energy and dark matter are placeholders because physicists do not know what they are
Dark matter can be observed although it is incredibly difficult to contain given its property
Dark energy acts like repulsive gravity since it is responsible for the expansion of galaxies

TimeSeeker
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Re: Philosophy of science-the first two and a half millennia.

Post by TimeSeeker » Sun Sep 30, 2018 9:33 pm

surreptitious57 wrote:
Sun Sep 30, 2018 9:26 pm
Dark matter can be observed although it is incredibly difficult to contain given its property
Sorry, but you are going to have to define your conception of 'observation' here. How can something that has no physical properties (optical, electromagnetic, gravitational, thermal or any other measurable/detectable properties) be 'observed'.

Explain the exact sense and the exact measurement tool/apparatus through which this observation happens.
surreptitious57 wrote:
Sun Sep 30, 2018 9:26 pm
Dark energy behaves like repulsive gravity and is responsible for the expansion of galaxies
I know what the theory says. I am looking for the empirical evidence.

As per my epistemic criteria for knowledge, I require verificationism ( https://en.wikipedia.org/wiki/Verificationism )
Otherwise you are no better than a theist.

uwot
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Re: Philosophy of science-the first two and a half millennia.

Post by uwot » Sun Sep 30, 2018 9:49 pm

surreptitious57 wrote:
Sun Sep 30, 2018 9:26 pm
Dark energy and dark matter are placeholders because physicists do not know what they are
That's true of pretty well every concept that is used in physics: charge, mass, spin, energy, time for example because actually
TimeSeeker wrote:
Sun Sep 30, 2018 9:33 pm
I am looking for the empirical evidence.
that's all we have. You cannot detect any of those things directly. They are all measured by the effect they have on other stuff, although spin appears to be intrinsic.

TimeSeeker
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Re: Philosophy of science-the first two and a half millennia.

Post by TimeSeeker » Sun Sep 30, 2018 9:51 pm

uwot wrote:
Sun Sep 30, 2018 9:49 pm
surreptitious57 wrote:
Sun Sep 30, 2018 9:26 pm
Dark energy and dark matter are placeholders because physicists do not know what they are
That's true of pretty well every concept that is used in physics: charge, mass, spin, energy, time for example because actually
TimeSeeker wrote:
Sun Sep 30, 2018 9:33 pm
I am looking for the empirical evidence.
that's all we have. You cannot detect any of those things directly. They are all measured by the effect they have on other stuff, although spin appears to be intrinsic.
I have no problem with charge, mass, spin, energy and time. Measurement is sufficient (for me).

How do you measure dark energy?

uwot
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Re: Philosophy of science-the first two and a half millennia.

Post by uwot » Sun Sep 30, 2018 9:58 pm

TimeSeeker wrote:
Sun Sep 30, 2018 9:51 pm
How do you measure dark energy?
Red shift.

surreptitious57
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Joined: Fri Oct 25, 2013 6:09 am

Re: Philosophy of science-the first two and a half millennia.

Post by surreptitious57 » Sun Sep 30, 2018 10:16 pm

Dark matter could be responsible for galaxies not flying apart and also be present in gravitational lensing and the cosmic microwave
background. It is very hard to detect given how it doesnt interact with ordinary matter or electromagnetic radiation. Most physicists
think it exists but there is currently no evidence for it since it can not be contained. It passes right through ordinary matter which is
why it is practically immune to detection. More sophisticated means of trapping it are needed before it can be properly investigated

TimeSeeker
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Re: Philosophy of science-the first two and a half millennia.

Post by TimeSeeker » Sun Sep 30, 2018 10:17 pm

uwot wrote:
Sun Sep 30, 2018 9:58 pm
TimeSeeker wrote:
Sun Sep 30, 2018 9:51 pm
How do you measure dark energy?
Red shift.
Red shift is red shift. You are measuring the expansion.

You are attributing it to dark energy. But that is a game of interpretation/speculation.

I can just as well say that the Big Bang was a white hole ( we are in a black hole) and the universe isn’t expanding but we are accelerating to the singularity.

Both are Untestable and unfalsifiable ;)

uwot
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Re: Philosophy of science-the first two and a half millennia.

Post by uwot » Sun Sep 30, 2018 10:53 pm

TimeSeeker wrote:
Sun Sep 30, 2018 10:17 pm
Red shift is red shift. You are measuring the expansion.

You are attributing it to dark energy. But that is a game of interpretation/speculation.
Pretty much the same is true of charge, mass, energy, gravity, strong, weak...
TimeSeeker wrote:
Sun Sep 30, 2018 10:17 pm
I can just as well say that the Big Bang was a white hole ( we are in a black hole) and the universe isn’t expanding but we are accelerating to the singularity.

Both are Untestable and unfalsifiable ;)
Well, that's why you devise experiments that test specific predictions.

TimeSeeker
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Joined: Tue Sep 11, 2018 8:42 am

Re: Philosophy of science-the first two and a half millennia.

Post by TimeSeeker » Sun Sep 30, 2018 11:30 pm

uwot wrote:
Sun Sep 30, 2018 10:53 pm
TimeSeeker wrote:
Sun Sep 30, 2018 10:17 pm
Red shift is red shift. You are measuring the expansion.

You are attributing it to dark energy. But that is a game of interpretation/speculation.
Pretty much the same is true of charge, mass, energy, gravity, strong, weak...
TimeSeeker wrote:
Sun Sep 30, 2018 10:17 pm
I can just as well say that the Big Bang was a white hole ( we are in a black hole) and the universe isn’t expanding but we are accelerating to the singularity.

Both are Untestable and unfalsifiable ;)
Well, that's why you devise experiments that test specific predictions.
Well no - it isn’t the same thing.

We are happy to leave the phenomena as they are. Quantified and without speculating cause.

What causes gravity? What causes energy? We don’t know! But we can measure it! That is good enough. All the SI units are grounded in things we can measure and in respect to one another. It is a closed system - it is internally consistent.

What causes the expansion of the universe? We don’t know but we can measure it (red shift) and that is good enough!

You have gone one step too far by attributing cause. And an unnecessary one at that. The expansion of the universe is uniform across the universe. So you can treat it as a constant quantified in redshift.

Gravity and energy are not uniform. It is precisely because they change in respect to other measurable things is why we can make predictions with them!

What experiments do you propose to test the causes of a constant? What are you going to predict? That the constant stays constant? That is as misguided line of enquiry as it gets!

uwot
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Joined: Mon Jul 23, 2012 7:21 am

Re: Philosophy of science-the first two and a half millennia.

Post by uwot » Sun Sep 30, 2018 11:56 pm

TimeSeeker wrote:
Sun Sep 30, 2018 11:30 pm
Well no - it isn’t the same thing.
I disagree.
TimeSeeker wrote:
Sun Sep 30, 2018 11:30 pm
We are happy to leave the phenomena as they are. Quantified and without speculating cause.
Who is we?
TimeSeeker wrote:
Sun Sep 30, 2018 11:30 pm
What causes gravity?
Einstein, for example, speculated on the cause of gravity; that's what spacetime is.
TimeSeeker wrote:
Sun Sep 30, 2018 11:30 pm
What causes energy?
Collisions mostly, actual and potential.
TimeSeeker wrote:
Sun Sep 30, 2018 11:30 pm
We don’t know! But we can measure it! That is good enough.
What causes the expansion of the universe? We don’t know but we can measure it (red shift) and that is good enough!
You have gone one step too far by attributing cause.
You are no more or less attributing the acceleration of the expansion of the universe implied by the observable red shift, than you are attributing the Earth going round the Sun because it is following a geodesic. It's completely superfluous from an instrumentalist point of view and many physicists don't bother. Others do.
TimeSeeker wrote:
Sun Sep 30, 2018 11:30 pm
And an unnecessary one at that. The expansion of the universe is uniform across the universe. So you can treat it as a constant quantified in redshift.
The thing that dark energy is invoked to explain is the apparent acceleration of the expansion. There is a lot of measuring to be done before it is clear whether any constants are involved.
TimeSeeker wrote:
Sun Sep 30, 2018 11:30 pm
Gravity and energy are not uniform.
Where do you know of that e doesn't equal mcc?
TimeSeeker wrote:
Sun Sep 30, 2018 11:30 pm
What experiments do you propose to test the causes of a constant? That is as misguided line of enquiry as it gets!
Ask me if I ever propose to test the cause of a constant.

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