Hacker News Reader

Comment by ars | Hacker News Reader

> what exactly would you use to plan and predict its journey

I guess you didn't read what I wrote. I will quote again for you: "Use a model to guide research".

> Would you wait until you have a way to measure what happens at the edge of the solar system before sending out your probe to measure it?

By all means - send out the probe. But until the probe returns data do not publish any papers purporting to know what the edge of the solar system looks like.

> The entirety physics is essentially a model.

No. It started as a model (or idea), but every single step was confirmed using the actual world, and not a model.

> If you want to completely know everything before you start trying to do anything, you'll get anything done.

Next time read what you are replying to so you can give a better response.

View on HN

> Use a model to guide research.

This I'll concede. I misinterpreted your point and tone as "don't rely on anything you haven't already measured". I would also agree that it's rather grating to read things that say "X totally happens (according to model Y)". But I don't think that it is inherently bad for one to say "Model Y predicts X".

> No. It started as a model (or idea), but every single step was confirmed using the actual world, and not a model.

This however, I do disagree with. It's still a model. It wasn't "confirmed"; it was "not disproven". Physics will always be a model. I don't see the problem with saying "this model turned out to be wrong so we need to come up with a better one" (exactly what's happening in the article). A large number of important breakthroughs in physics were from scientists demonstrating the failures of models or running into them accidentally (see caloric theory and the Michelson–Morley experiment).

> But I don't think that it is inherently bad for one to say "Model Y predicts X".

I do. Not because the sentence in and off itself is bad, but rather because when the sentence is repeated it gets changed to "We know X because of Y."

> Physics will always be a model.

Maybe we have different meanings for the word model.

I suspect you are using the word model like a "model car". i.e. a description of what something is.

I mean it in the term of "model these variables", ie. use a computer to put in variables and hope you programmed everything correctly and get a result of what will happen.

I'm not using it in the descriptive sense, but rather the action sense.

> I don't see the problem with saying "this model turned out to be wrong so we need to come up with a better one" (exactly what's happening in the article).

Nothing wrong with saying that, but that's not what actually happened. Instead the model of the boundary was taught as fact (for example I expect that if you read the wikipedia article on it from 5 years ago it would talk as if we had a pretty good idea of what the boundary looked like).

If, it was simply used to decide which experiments to prioritize on the spacecraft that would be fine. But that's not all that the model was used for.

I'm sure in the original they were careful to call it a model, and an idea, etc. But in wider use (even scientific articles) it was understood as fact.

Are you actually kidding?

"But until the probe returns data do not publish any papers purporting to know what the edge of the solar system looks like."

I'm pretty sure that no decent scientist ever 'purports to know' what the edge of the solar system looks like - they are merely using what evidence they have available to make an educated guess and try to get a workable model of it.

This is how science works.

You make a model, test it and finds the evidence does not fit your model. You then modify your model.

Also, you seem to be suggesting that all of, say, theoretical physics is necessarily worthless. What about pure maths? String theory? All of these things are just models, and have no basis in reality. What of them?

Reply on news.ycombinator.com