主题：【原创】什么是科学以及我们如何走科学的道路 -- 曾自洲

现在很多在网上争论所谓科学不科学的人，其实根本不知道什么是科学

随着时代的发展，科学至少有四种定义方式，第四种是现代得到广泛认可的定义

Today, in contrast to the seventeenth century, few would deny the central importance of science to our lives, but not many would be able to give a good account of what science is. To most, the word probably brings to mind not science itself, but the fruits of science, the pervasive complex of technology that has transformed all of our lives. However, science might also be thought to include the vast body of knowledge we have accumulated about the natural world. There are still mysteries, and there always will be mysteries, but the fact is that, by and large, we understand how nature works.

A. Francis Bacon’s Scientific Method

But science is even more than that. If one asks a scientist the question, What is science?, the answer will almost surely be that science is a process, a way of examining the natural world and discovering important truths about it. In short,

the essence of science is the scientific method.

That stirring description suffers from an important shortcoming. We don’t really know what the scientific method is. There have been many attempts at formulating a general theory of how science works, or at least how it ought to work, starting, as we have seen, with Sir Francis Bacon’s. Bacon’s idea, that science proceeds through the collection of observations without prejudice, has

been rejected by all serious thinkers. Everything about the way we do science—

the language we use, the instruments we use, the methods we use—depends on

clear presuppositions about how the world works. Modern science is full of

things that cannot be observed at all, such as force fields and complex molecules.

At the most fundamental level, it is impossible to observe nature without having

some reason to choose what is worth observing and what is not worth observing.

Once one makes that elementary choice, Bacon has been left behind.

B. Karl Popper’s Falsification Theory

In this century, the ideas of the Austrian philosopher Sir Karl Popper have had

a profound effect on theories of the scientific method.5 In contrast to Bacon,

Popper believed all science begins with a prejudice, or perhaps more politely, a

theory or hypothesis. Nobody can say where the theory comes from. Formulating

the theory is the creative part of science, and it cannot be analyzed within

the realm of philosophy. However, once the theory is in hand, Popper tells us,

it is the duty of the scientist to extract from it logical but unexpected predictions

that, if they are shown by experiment not to be correct, will serve to render the

theory invalid.

Popper was deeply influenced by the fact that a theory can never be proved

right by agreement with observation, but it can be proved wrong by disagreement

with observation. Because of this asymmetry, science makes progress

uniquely by proving that good ideas are wrong so that they can be replaced by

even better ideas. Thus, Bacon’s disinterested observer of nature is replaced by

Popper’s skeptical theorist. The good Popperian scientist somehow comes up

with a hypothesis that fits all or most of the known facts, then proceeds to attack

that hypothesis at its weakest point by extracting from it predictions that can be

shown to be false. This process is known as falsification.

Popper’s ideas have been fruitful in weaning the philosophy of science away

from the Baconian view and some other earlier theories, but they fall short in a

number of ways in describing correctly how science works. The first of these is

the observation that, although it may be impossible to prove a theory is true by

observation or experiment, it is nearly just as impossible to prove one is false by

these same methods. Almost without exception, in order to extract a falsifiable

prediction from a theory, it is necessary to make additional assumptions beyond

the theory itself. Then, when the prediction turns out to be false, it may well be

one of the other assumptions, rather than the theory itself, that is false. To take

a simple example, early in the twentieth century it was found that the orbits of

the outermost planets did not quite obey the predictions of Newton’s laws of

gravity and mechanics. Rather than take this to be a falsification of Newton’s

laws, astronomers concluded the orbits were being perturbed by an additional

unseen body out there. They were right. That is precisely how the planet Pluto

was discovered.

The apparent asymmetry between falsification and verification that lies at the

heart of Popper’s theory thus vanishes. But the difficulties with Popper’s view

go even beyond that problem. It takes a great deal of hard work to come up

with a new theory that is consistent with nearly everything that is known in any

area of science. Popper’s notion that the scientist’s duty is then to attack that

theory at its most vulnerable point is fundamentally inconsistent with human

nature. It would be impossible to invest the enormous amount of time and

energy necessary to develop a new theory in any part of modern science if the

primary purpose of all that work was to show that the theory was wrong.

This point is underlined by the fact that the behavior of the scientific community

is not consistent with Popper’s notion of how it should be. Credit in

science is most often given for offering correct theories, not wrong ones, or for

demonstrating the correctness of unexpected predictions, not for falsifying them.

I know of no example of a Nobel Prize awarded to a scientist for falsifying his or

her own theory.

C. Thomas Kuhn’s Paradigm Shifts

Another towering figure in the twentieth century theory of science is Thomas

Kuhn.7 Kuhn was not a philosopher but a historian (more accurately, a physicist

who retrained himself as a historian). It is Kuhn who popularized the word

paradigm, which has today come to seem so inescapable.

experience that it really happens that way. Kuhn’s contribution is important. It

gives us a new and useful structure (a paradigm, one might say) for organizing

the entire history of science.

Nevertheless, Kuhn’s theory does suffer from a number of shortcomings as an

explanation for how science works. One of them is that it contains no measure

of how big the change must be in order to count as a revolution or paradigm

shift. Most scientists will say that there is a paradigm shift in their laboratory

every six months or so (or at least every time it becomes necessary to write

another proposal for research support). That isn’t exactly what Kuhn had in

mind.

Another difficulty is that even when a paradigm shift is truly profound, the

paradigms it separates are not necessarily incommensurate. The new sciences of

quantum mechanics and relativity, for example, did indeed show that Newton’s

laws of mechanics were not the most fundamental laws of nature. However,

they did not show that they were wrong. Quite the contrary, they showed why

Newton’s laws of mechanics were right: Newton’s laws arose out of new laws

that were even deeper and that covered a wider range of circumstances

unimagined by Newton and his followers, that is, things as small as atoms, or

nearly as fast as the speed of light, or as dense as black holes. In more familiar

realms of experience, Newton’s laws go on working just as well as they always

did. Thus, there is no ambiguity at all about which paradigm is better. The new

laws of quantum mechanics and relativity subsume and enhance the older

Newtonian world.