

Science Only Has Two Legs - Rickasaurus
http://portal.acm.org/ft_gateway.cfm?id=1810892&type=html&coll=GUIDE&dl=GUIDE&CFID=102012981&CFTOKEN=18184364

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frossie
I agree entirely with the OP, but I have also seen people treating computation
as a "third leg", to the detriment of progress I think.

Let me concoct a trivial example. Suppose you wanted to know whether a bowling
ball would drop from the top of a building faster than a tennis ball. You can
do this without reference to theory - just go out and experiment. Doing the
experiment would not give you the complete physical picture perhaps, but it
would certainly

(a) answer your narrow question and

(b) give you a constraint that any theory must explain.

The problem is that there is a class of research where people who are faced
with this question, would set up a computer model. Now let's say they didn't
realise they had to model air resistance. They will discover something all
right, but it will neither answer the narrow question, nor provide a robust
constraint for theory.

In other words, playing around with computational models is _not_ , by itself,
theory or experimentation unless you are very careful on how you tie it back
to the physical world.

~~~
xtacy
The example you suggested is probably too simple; one should realise that the
actual experiment might be very difficult, if not impossible to carry out.
Consider a theory of galaxy collisions---I am unable to see any way of testing
out the hypothesis, unless the equations are simple enough.

A computer program just a different language of expressing the theory...
Hence, I see no reason why one should separate theory and computer programs.

~~~
Retric
Modeling is at best a thought experiment. It can only show you if a theory is
reasonably self consistent based on your assumptions not if it's actually
true.

PS: There are limits on science, and the ability to conduct an actual
meaningful exponent is one of the largest ones.

~~~
jshen
I think there's more to it than that. For example, a model can tell you if
something isn't true which is very significant. It can also make predictions
that can then be tested.

These two alone are much more than a mere thought experiment.

~~~
brg
I am having a hard time seeing the different.

A thought experiment can tell you that if A then B. A model is a means of
producing a prediction B from A by means of long, complicated calculations
instead of simple logical inferences. In both cases the conclusions should be
evaluated before accepted as physical truth.

~~~
jshen
what do you believe is the different between a theory and a thought
experiment?

~~~
brg
I would say a theory is a hypothesis which has been tested. A thought
experiment can be part of hypothesis creation.

~~~
jshen
and a model can very easily be a hypothesis which can be tested. I.e. it's far
more like a theory than a thought experiment.

~~~
brg
Perhaps we're splitting hairs. But this doesn't sit right with me.

Consider what is meant by a thought experiment in popular literature. Take
Einstein's elevator. Would you call that "Einstein's elevator theory?" Or is
that a prediction based on the theory of equivalence?

Maybe in this vein a clear distinction is that a thought experiment is a proof
discovery technique. It is working with heuristics and intuition. At the end
there is something; a statement or prediction that seems right. But no matter
how much intuition confirms it, in the physical sciences it needs to be tested
and in the mathematical sciences it needs a formal proof. Beyond that, it is
just another hypothesis. After that it leads to a theory.

~~~
Confusion
With all due respect, but you're both not just splitting hairs: you're
splitting hairs about something you don't know enough about. There's a whole
body of literature on the subject and you're not going to reinvent all of that
in the course of this small discussion. If neither of you have heard of, for
instance, Carl Hempel, then this discussion is completely pointless.

If you don't standardize your terminology first, then you're just discussing
the boundaries of your personal definitions, instead of embarking on actual
intellectual discovery of the terrain.

~~~
brg
This discussion is an 'intellectual discovery' for its participants. Its
unfortunate you wish to hinder that through dismissive remarks instead of
constructively participating.

~~~
Confusion
When I was 12, I once had a night-long discussion with a friend about the
implications of faster-than-light travel. Once I learned some actual physics,
I realized none of that discussion made any sense at all.

Something isn't intellectual discovery just because information is exchanged
and both people feel they are learning stuff. Intellectual discovery makes
sense if you are trying to structure the knowledge and are connecting it to
knowledge you already have. Without things to connect it to, such as a shared
definition of 'theory', you end up running around in circles.

It's like being dropped into a maze and not trying to solve it, but just
running around in it. It may be fun, and you won't hear me complain, but as
soon as someone starts wondering whether they are going too much into the
details of solving it ("maybe I'm splitting hairs"), I feel obliged to point
out they haven't really started to solve it. They've just been randomly
discovering the territory, not noticing whether they returned to the same
point several times.

I'm not trying to be disparaging; I'm just pointing out that talk of
'splitting hairs' is really premature.

~~~
jshen
I often find it highly useful to flesh out terrain in my own mind before
exploring the literature. You're remarks were extremely condescending and you
could have made the same point without the poor tone.

Oddly, you nearly admit the usefulness of it. "They've just been randomly
discovering the territory". Discovering territory is valuable, whether it's
random or not!

But the oddest thing is that you don't provide any useful information. You
don't link to a page with the info you think we should read, or to a book on
the matter, or a paper. Nothing, but condescension.

~~~
Confusion
I'm sorry, it was not my intention to be condescending; merely to be critical.
Searching for 'philosophy of science' should provide plenty of resources;
which ones suit _you_ is impossible for me to guess, because it strongly
depends on background/prior knowledge, which is why I refrained from advising
anything specific.

As a starting point,
<http://www.teach12.com/ttcx/CourseDescLong2.aspx?cid=4100> may be a pretty
decent introduction. There are torrents floating around if you want a taste.

~~~
jshen
The link looks interesting, but does it talk specifically about models and
their relation to theories which is what we were discussing that you found to
be a waste of time

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lotharbot
The two legs of science are more accurately referred to as _theory_ and
_observation_. Experimentation is one way to gather observations, but it is
not the only one. Astronomy involves a lot of observation of stars, which are
some distance outside of the laboratory and definitely not in an experimenter-
controlled environment.

I would classify numerical/computational models, along with mathematical and
philosophical models, under "theory". Number-crunching and heavy data analysis
is a way to categorize and present observations. None of these deserve to be
treated as new and separate legs of science; they are merely subsets of the
existing legs of _theory_ and _observation_.

~~~
dctoedt
This is an important distinction that should be more-widely propagated. I once
got into a debate with a very conservative Episcopal priest who was then one
of the clergy at my parish. He criticized "scientism" on grounds that the
touchstone of science is experimentation (he said), and it's blasphemous to
claim you can experiment with God. I responded that the touchstone of science
is _observation,_ and that there's no _a priori_ reason we can't "observe" God
at least indirectly (cf. Romans 1.20).

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mattrepl
This article appears to be a response to the new _Journal of Computational
Science_ whose editor-in-chief promotes computational science as separate from
theory and experimentation.

The inciting text can be found in the description section here (click to
expand the full Aims & Scope section):
[http://www.elsevier.com/wps/find/journaldescription.cws_home...](http://www.elsevier.com/wps/find/journaldescription.cws_home/721195/description)

An excerpt:

"Computational Science is a rapidly growing multi- and interdisciplinary field
that uses advanced computing and data analysis to understand and solve complex
problems. It has reached a level of predictive capability that now firmly
complements the traditional pillars of experimentation and theory." - Peter
Sloot, Editor-in-Chief

~~~
_delirium
Part of that view, at least as I understand it, was driven by a similar view
from the theory side, that computational modeling isn't theory in the
traditional sense. From a more academic-politics point of view, computational
modeling is often a difficult sell in traditional theoretical publication
venues as well, which prefer the computation to be minimal and the equations
to be hand-worked--- big computational models are seen more as something that
belongs to engineering. So the pushback is: fine, it's not theory, but it's
still important to science, and it's clearly not experimentation, so it must
be a third thing, and we'll start our own publication venues for it.

I do agree more with this article that it's a kind of theory, but I think the
people who disagree aren't only computational science people, but also (some)
theory people.

------
brg
I also concur. Computational modeling should be viewed as part of hypothesis
formation. Similar to mathematical manipulation, it is a precursor to
experimentation. Computational models are too often presented as evidence of a
physical theory, instead of a prediction in need of experimental support. We
see this in every field; social network theory, epidemiology,
environmentalism, even papers in combinatorial optimization!

Interestingly, perhaps the field that most strongly holds to the view that
models need testing is weapons research.

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akozak
If it's true that computation is just an extension of two "traditional" legs
of science, then it follows that the steps taken in computation as part of
scientific research ought to be as public as the steps taken in theory and
traditional experimentation. That is, opening up the source code and data to
peer review and scrutiny becomes just as important as describing methods in a
non-computational study.

In other words, computational transparency is important if computation is just
an extension of the traditional scientific method.

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sdwytkeisjeufjw
the concept of a new leg is something that allow us to change significantly
the way in which we move. A car is not a new leg, a leg grows with the body.

So the question is: is computational science like a car or like a leg. Is only
a tool or is something that will make a change in the way we think and
conceive experiments, in the way we consider thinks to be possible and shape
our future?

In ancient times there was only one leg for science, that was authority. I see
no problem which the three or four legs concept. The only thinks I would
consider silly is to confuse a leg with a finger. Anyway, if you don't want to
use body analogies, don't ask for know many legs science has in the first
place.

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zeynel1
i think op is making a good point - there is nothing more to science than
computed minus measured equals error

what a scientist does is to make a model which is the computed than she makes
measurements and obtains errors - the error or the residuals - is the
knowledge

people may call computeds -theory -model -hypothesis -framework and similar
words but the process is always the same

for instance ptolemaic theory is a mathematical framework that results in very
good residuals which means that ptolemaic model saves the naked eye
observations very well

if as the op writes an experiment generates -40 terabytes of raw data per
second- you still have to model it and obtain residuals

but the real interesting problem facing contemporary science is that now what
is -computed- and what is -measured- are no longer clearly separated

