Science's Big Query: What Can We Know, and What Can't We?

The Wall Street Journal ^ | Friday, May 30, 2003 | SHARON BEGLEY

[TroutStalker]

What if stalactites could talk? If these icicle-shaped mineral deposits somehow preserved the sound waves that impinged on them as they grew, drop by drop, from the ceilings of caves, and if scientists figured out how to recover the precise characteristics of those waves, then maybe they would also be able to use stalactites like natural voice recorders and recover the conversations of ancient cave dwellers. Is it more far-fetched than recovering conversations from magnetized particles on an audio tape?

[geopyg]

There are no knowns.

There are things we know that we know.

There are known unknowns. That is to say, there are things we now know we don't know.

But there are also unknown unknowns,
things we do not know we don't know.

Secretary of Defense Donald Rumsfeld
on the war on terrorism.

[geopyg]

There are no knowns.

There are things we know that we know.

There are known unknowns. That is to say, there are things we now know we don't know.

But there are also unknown unknowns,
things we do not know we don't know.

Secretary of Defense Donald Rumsfeld
on the war on terrorism.

[Physicist]

But this line

"Roman blacksmiths from their shackles cried,"

had me stumped.

I attach both a figurative and a literal meaning to the word "shackles". The literal meaning is that physical iron shackles dating from Roman times held the voices of the Latin-speaking blacksmiths that made them. The figurative meaning is that their voices--the ghostly echo of their own selves--were bound up (shackled, as it were) for two thousand years.

Does it mean that your "dream invention" unlocked sound from metal artifacts produced by (enslaved?) Roman blacksmiths and from Franklin's harmonica, but from nothing else ever?

As for the last line, it's not that nothing more was ever heard, but that it was never anything particularly useful or enlightening. In my dream, even Franklin's fragment of a question to a glazier turned into a farce: the chief effect was to spark a flurry of plays and TV shows about Franklin, who inevitably, and in a queerly distorted voice, would end up asking a partial question of the man he'd commissioned to make the Glass Harmonica. The economy ended up geared towards producing useless little snippets of sound from the past.

[Mind-numbed Robot]

....it's somewhere at all times, right?

Yes, but when you introduce momentum, or movement, you can't have just one place. You need a sequence of places and therefore no ONE place. As a result, it seems to me, the concept of momentum and position simultaneously is mutually exclusive.

[Aquinasfan]

Hopefully they take a course in philosophy along the way. From what I've read, few scientists seem to be able to distinguish between natural science and philosophy, at least the atheist/materialist ones, Carl Sagan being a good example. He began his book, "Cosmos," with the line, "The universe is all that is or ever was or ever will be..."

[Aquinasfan]

Not always. The Heisenberg Uncertainty Principle and black hole "no-hair" theorems come immediately to mind.

OK. Do you have a law degree too?

[Physicist]

OK. Do you have a law degree too?

No, I don't.

[RightWhale]

They should. Maybe most do. My philosophy prof used to amuse himself at parties by approaching various PhDs and starting to talk about philosophy or in a philosophic way. When he quickly established that his quarry knew no more than do ordinary freshman about philosophy, he would ask if the Ph in PhD meant philosophy. Great fun!

[PatrickHenry]

I thought it was widly known that science was originally considered a branch of philosophy, called "natural philosophy," to distinguish it from theology. People we now call scientists were, as recently as Darwin's time, called philosophers.

[RightWhale]

I have always thought of it that way. A lot of people don't, however, so when conversing with strangers we have to ask a question or two before proceeding.

[ido_now]

Philosophy has proven abolutely, beyond any doubt, the fact that: "Nothing can be known, therefore nothing can be proven to be true!"

See Proof At: "http://www.halfwhit.edu.your-kids-college/For-$40,000/Year/Sucker.html"

[<1/1,000,000th%]

Wait until I tell my wife!

[Richard Kimball]

bttp

[tortoise]

So, are they saying that the future we see in the movie GATACA would be impossible?

Generally speaking, yes. Having the genome of a person could be viewed roughly as having the code to a computer program. What this doesn't allow you to do is predict a future state of the program when it is actually running. It is computationally intractable to predict the personality and intelligence of some future state given only the starting state. At best the genome allows you to make probabilistic guesses as to the bulk properties of a person in the abstract, but tells you exactly dick about the characteristics of an instance at some specific point in time. A basic limitation per computational theory.

[RightWhale]

It is computationally intractable to predict the personality and intelligence of some future state given only the starting state.

The State doesn't rely on perfect DNA. It nurtures and monitors, and adjusts as well, and keeps doing this all the way to the end.

[js1138]

You need to get more sleep. ;^)

[Chemist_Geek]

I thought it was widly known that science was originally considered a branch of philosophy, called "natural philosophy," to distinguish it from theology. People we now call scientists were, as recently as Darwin's time, called philosophers.

Correct. A science Ph.D. is a doctorate of (natural) philosophy.

[Chemist_Geek]

Yes, but when you introduce momentum, or movement, you can't have just one place. You need a sequence of places and therefore no ONE place. As a result, it seems to me, the concept of momentum and position simultaneously is mutually exclusive.

No, it's not. You wrote, yourself, there there is a sequence of places that the body occupies. It may do so for an infinitesimally short period of time, but, it does occupy a place.

In one dimension, a body's position can be given by:
x(t) = a·t² + v·t + x(0), where a is acceleration, v is velocity, and x(0) is the body's initial position. That position x(t) can be evaluated for any instant of time, t.

[Mind-numbed Robot]

Regardless of the formulas, it seems self-evident that a position in space is fixed, not moving, and that once in motion it cannot be in a fixed place while moving. No matter how infinitesimal the moment of being in a position, for that moment there is no movement, ergo, no momentum. From the article:

And physicists showed that the laws of quantum mechanics prevent us from knowing simultaneously both the position and the momentum of a subatomic particle.

Do you not agree with that? All I am saying is that that is a self-evident truth that one may be able to illustrate with mathematical formulas but that the formulas are not necessary. It is self-evident that you can't be both in motion and at rest at the same time.

[PatrickHenry]

It is self-evident that you can't be both in motion and at rest at the same time.

Well now, that depends on the observer's frame of reference. To me, I'm at rest. To an observer on the moon, I'm in motion.