Science is built up with facts, as a house is with stones. Buta collection of facts is no more a science thana heap of stones is a house. HenriPoincaré (1903)
At the heart of science is an essential balance between two seemingly contradictory attitudes; an openness to new ideas (no matter how bizarre or counterintuitive they may be) and the most ruthless skeptical scrutiny of all ideas, old and new. This is how deep truths are winnowed from deep nonsense. Carl Sagan (1934-1996)
...You should always ask "why not?" but realize that usually there's a goddamn reason why not. Murray Gell-Mann (1929-2019)
A physical theory is not an explanation. It is a system of mathematical propositions, deduced from a small number of principles,which aim to represent as simply, as completely, and as exactly as possible a set of experimental laws. Pierre Dûhem (1861-1916)
whitehorse456 (Yahoo!2007-08-08) Will the law of gravity always remain confined to atheory ?
Nothing can be stated clearly unless proper meanings are assigned tocrucial words like theory and law in a scientific context. In particular, the word "theory" is not an insult (as in the silly saying "it's just a theory"). A theory is simply a consistentbody of scientific knowledge not yet disproved by experiment (at a given level of precision).
In experimental sciences, a theory can never be proved for certain;it can either be disproved by experiment or be consistentwith it. This is precisely was makes a theory scientific. A statement that can't possibly be disproved by experiment may be highly respectable but it does no belong in an experimental science... It might be mathematics, philosophy or religion, but it's not physics.
Now that we have the basic vocabulary straight,we may discuss the example of gravitation. Gravity is a physical phenomenon which is obvious all around us. As such, it's begging for a scientific theory to describe it accurately and consistently. A law is a rule within a theory (like Newtonian mechanics). Newton's own inverse square law of Universal gravitation describes gravity extremely wellin terms of Newtonian mechanical forces. Loosely stated:
Two things always attract each other in direct proportion of their massesand inversely as the square of the distance between them.
We do know that the Newtonian theory does not provide the ultimate law for gravity. General Relativity (GR) provides more accurateexperimental predictions in extreme conditions (e.g., a residual discrepancy in the motion of the perihelion of Mercuryis not explained by Newtonian theory but is accounted for by GR).
Does this mean Newton's theory is wrong ? Of course not. Until we have a "Theory of Everything" (if such a thing exists) any physical theory only has a limited range of validity,where its predictions are accurate at a stated level of precision (stating the claimed precision is very important in Science;an experimental prediction is meaningless without it). The Newtonian theory predicts the motion of planetsin theSolar System to many decimal places, over eons... That's all we ask of it and that's what makes it so valuable.
Even General Relativity is certainly not the ultimate theory of gravitation. We know that much because GR is a classical theory,as opposed to a quantum theory (i.e., a theory obeyingquantum logic). So, GR is not mathematically compatible with quantum phenomenawhich are so obvious at a small scale.
Science is just a succession of better and better approximations. This is what makes it nice and exciting. If we insisted at all times on "the whole truth and nothing but the truth"no meaningful scientific statement could ever be made.
As a consistent body of knowledge,each theory allows you to make such statements freely,knowing simply that the validity of your discourse is only restrictedby the general conditions of applicability of that theory. Without sucha framework, scientific discourse would be crippled into utter uselessness.
(2007-07-14) It's easier to isolate the causes of a phenomenon when we create them.
Experiments are now so intertwined with Science that we may forgetthat good Science can be performed without experiments. There are no experiments in Astronomy. Astronomers have to be content with observing phenomena over whichthey have no control.
The same can be true, albeit less systematically, of other sciences aswell. There was a time when particle physicists relied onrandom cosmic rays of unknown origin for something worth observing.
Similarly, experiments in evolutionary biology can only be performedon simple lifeforms that reproduce so rapidly that a large numberof generations can be observed in a reasonable amount of time. The power of natural selection established under such controlledconditions can be extrapolated to more complex lifeforms with longer lifetimesjust like physical laws established in the laboratory areextrapolated to astronomical objects.
Paradoxically, the aim of Science is to provide ways to dispense with countless experiments. For example,it is now pointless to play with objects likegears,wheels ormagnets in the hopeof producing perpertual motion when wehave established to a fabulous degree of precisionthat all the simple components of suchsystems obey conservation laws that preclude it (includingrelativistic mechanics,electromagnetism,thermodynamics andquantum theory). Scientific advances come from discovering new aspects of reality (e.g.,radioactivity in 1896) new paradigms (e.g.,quantum logic) or clever ways to harness nature (modern technology).
From a pedagogical standpoint, it's useful to repeat simple-mindedexperiments to stress the fact that Science is ultimately based onobservation, not dogma. Of course, no one will ever be able to actually repeat all the experiments on which basic scientific knowledge is based, but we shouldat least be satisfied that we could reproduce any key experiment we like.
Occasionally, a pedagogical demonstration turns into a flopwhich the teacher may or may not explain correctly... Watch carefully the videos quoted in the footnote below, whereJulius Sumner Miller(1909-1987) makes the following statements pertaining to the time it takes forthings to roll down an inclined plane, starting from rest:
All hoops roll alike (hollow cylinders).
All disks roll alike (homogeneous cylinders). They beat all hoops.
All spheres roll alike (homogeneous spheres). They beat all disks.
He then proceeds to demonstrate this on a wooden inclined plane. In some cases, he fails miserably but allows the showmanship to prevailover his scientific training, using apologetic sentences like:
"It will be a little difficult to check this."
"If our provisions for Nature were of an adequate sort, I could show youthe following phenomena..."
"We have a little trouble with this board, but that's another piece of evidencethat, when you deal with Nature, you must meet Her requirements... A little difficult to show it (the hazards of experiments) but I'm going to tell you: All spheres beat all disks."
Can you discover the fallacy that Julius Sumner Miller chose to ignore?
(2007-07-15) The key ideas behind modern science.
Mathematics serves as the language of all natural sciences, but it's not itselfa natural science.
That year, an academic competition was created in pre-revolutionary Francewhich is still in existence: Every year, selected graduating high-school students compete in what's called theConcoursgénéral (short for Concours général deslycées et collèges).
The institution temporarily disappeared during the French revolution and, againfrom 1904 to 1922, because some top lycées reportedley placed too much emphasis on it. It was threatened again in the early 1980s, as the socialist government of Francedidn't consider it politically correct to stress excellence. (In 1983, the French minister of education didn't see fit to attendthe award ceremonies of the International Mathematical Olympiads, which were held in Paris.)
In recent years, the Concours Général has regained much of its former prestige, and then some...
Concours Général of 1973 (philosophy for science majors):
At the age of 17, I had the honor to represent my school in mathematics and philosophy (I was coached after hours by my philosophy teacher, Bernard Lefebvre). Against some expectations, I didn't do very well in mathematics but I nailedit in philosophy and made the front page of the local paper (although I didn't win the top prize; two other people, somewhere in France, were rankedahead of me). The question we were asked was:
In what sense can we distinguish between true and false sciences ?
Thus, even at that young age, I must have known already... I must have knownthat there ought to be more to Science than scientific appearances !
As Science progresses, the time it takes for anyone to obtain a workingknowledge of the state-of-the-art in any field keeps increasing but,arguably, motivated teenagers can still get a fairly good grasp of whatdistinguishes good science and pseudoscience. Yet, adults and trained scientists may go astray...
It's probably uncharitable to expose people who are trying to make a scientificcontribution without the benefit of a proper scientific education. Unfortunately,it seems next to impossible to provide some wannabe-scientists with the elementsthat would make them wise critics of their own theories. Even at my own modest level of notoriety, I am regularly confronted with that naggingproblem. A few gurus and luminaries chose a humorous approach to the issue:
On the other hand, some trained scientists who make outrageous claimsmay fool everybody except their better peers. They can even fool themselves If they don't fool themselves, they are simply liars orcrooks and things are easier to sort out!
(2011-10-22) Scientific investigation goes on in spite of distorted media reports.
In a CERN press release dated 2011-09-23 (which has been corrected and updated several times since) it was originally announced that the OPERA team at Grand-Sasso was reportingthe detection of neutrinos traveling faster than light,as part of a experiment conducting jointly with CERN.
This careless release (whose original content went against the verycore of modern physics) started a media circus to which virtually all scientists witha modicum of media visibility had to reply while the error wasbeing corrected. Eventually, at least two OPERA leaders lost their jobs.
