l******r
发帖数: 3472 | 1 文科生就不要看了，看了也看不懂。
各位看完了，看懂了，写个读后感吧。
A Brief History of Time 第一章中的一段。
In order to talk about the nature of the universe and to discuss questions such as whether it has a beginning or an end, you have to be clear about what a scientific theory is. I shall take the simpleminded view that a theory is just a model of the universe, or a restricted part of it, and a set of rules that relate quantities in the model to observations that we make. It exists only in our minds and does not have any other reality (whatever that might mean).
A theory is a good theory if it satisfies two requirements. It must
accurately describe a large class of observations on the basis of a model that contains only a few arbitrary elements, and it must make definite predictions about the results of future observations. For example, Aristotle believed Empedocles's theory that everything was made out of four elements, earth, air, fire, and water. This was simple enough, but did not make any definite predictions. On the other hand, Newton’s theory of gravity was based on an even simpler model, in which bodies attracted each other with a force that was proportional to a quantity called their mass and inversely proportional to the square of the distance between them. Yet it predicts the motions of the sun, the moon, and the planets to a high degree of accuracy.
Any physical theory is always provisional, in the sense that it is only a hypothesis: you can never prove it. No matter how many times the results of experiments agree with some theory, you can never be sure that the next time the result will not contradict the theory. On the other hand, you can disprove a theory by finding even a single observation that disagrees with the predictions of the theory. As philosopher of science Karl Popper has emphasized, a good theory is characterized by the fact that it makes a number of predictions that could in principle be disproved or falsified by observation. Each time new experiments are observed to agree with the predictions the theory survives, and our confidence in it is increased; but if ever a new observation is found to disagree, we have to abandon or modify the theory.
At least that is what is supposed to happen, but you can always question the competence of the person who carried out the observation. | p****e
发帖数: 183 | 2 这篇讲得透彻，多谢。最关键是这句：
Any physical theory is always provisional, in the sense that it is only a
hypothesis: you can never prove it. No matter how many times the results of
experiments agree with some theory, you can never be sure that the next time
the result will not contradict the theory. On the other hand, you can
disprove a theory by finding even a single observation that disagrees with
the predictions of the theory.
就是说某人非要给物理、医学理论做什么“数学证明”，那他基本上是民科。
such as whether it has a beginning or an end, you have to be clear about
what a scientific theory is. I shall take the simpleminded view that a
theory is just a model of the universe, or a restricted part of it, and a
set of rules that relate quantities in the model to observations that we
make. It exists only in our minds and does not have any other reality (
whatever that might mean).
that contains only a few arbitrary elements, and it must make definite
predictions about the results of future observations. For example, Aristotle
believed Empedocles's theory that everything was made out of four elements,
earth, air, fire, and water. This was simple enough, but did not make any
definite predictions. On the other hand, Newton’s theory of gravity was
based on an even simpler model, in which bodies attrac: ted each other with
a force that was proportional to a quantity called their mass and inversely
proportional to the square of the distance between them. Yet it predicts the
motions of the sun, the moon, and the planets to a high degree of accuracy.
hypothesis: you can never prove it. No matter how many times the results of
experiments agree with some theory, you can never be sure that the next time
the result will not contradict the theory. On the other hand, you can
disprove a theory by finding even a single observation that disagrees with
the predictions of the theory. As philosopher of science Karl Popper has
emphasized, a good theory is characterized by the fact: that it makes a
number of predictions that could in principle be disproved or falsified by
observation. Each time new experiments are observed to agree with the
predictions the theory survives, and our confidence in it is increased; but
if ever a new observation is found to disagree, we have to abandon or modify
the theory.
the competence of the person who carried out the observation.
【在 l******r 的大作中提到】
: 文科生就不要看了，看了也看不懂。
: 各位看完了，看懂了，写个读后感吧。
: A Brief History of Time 第一章中的一段。
: In order to talk about the nature of the universe and to discuss questions such as whether it has a beginning or an end, you have to be clear about what a scientific theory is. I shall take the simpleminded view that a theory is just a model of the universe, or a restricted part of it, and a set of rules that relate quantities in the model to observations that we make. It exists only in our minds and does not have any other reality (whatever that might mean).
: A theory is a good theory if it satisfies two requirements. It must
: accurately describe a large class of observations on the basis of a model that contains only a few arbitrary elements, and it must make definite predictions about the results of future observations. For example, Aristotle believed Empedocles's theory that everything was made out of four elements, earth, air, fire, and water. This was simple enough, but did not make any definite predictions. On the other hand, Newton’s theory of gravity was based on an even simpler model, in which bodies attracted each other with a force that was proportional to a quantity called their mass and inversely proportional to the square of the distance between them. Yet it predicts the motions of the sun, the moon, and the planets to a high degree of accuracy.
: Any physical theory is always provisional, in the sense that it is only a hypothesis: you can never prove it. No matter how many times the results of experiments agree with some theory, you can never be sure that the next time the result will not contradict the theory. On the other hand, you can disprove a theory by finding even a single observation that disagrees with the predictions of the theory. As philosopher of science Karl Popper has emphasized, a good theory is characterized by the fact that it makes a number of predictions that could in principle be disproved or falsified by observation. Each time new experiments are observed to agree with the predictions the theory survives, and our confidence in it is increased; but if ever a new observation is found to disagree, we have to abandon or modify the theory.
: At least that is what is supposed to happen, but you can always question the competence of the person who carried out the observation.
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