Section outline

  • A large cartoon rabbit next to a person contemplating two hypotheses about its size.

    Although this cartoon pokes fun at scientific hypotheses, the concept of hypothesis is one of the most important in science . Scientific investigations discover evidence that helps science advance, and the purpose of scientific investigations generally is to test hypotheses. Finding evidence to support or disprove hypotheses is how science advances.
    ::尽管这一漫画在科学假设中引以为乐,但假设的概念是科学中最重要的概念之一。 科学调查发现了有助于科学进步的证据,而科学调查的目的通常是测试假设。 寻找支持或否定科学进步的证据是科学进步的方式。

    What is a Scientific Hypothesis?
    ::什么是科学假设?

    The word hypothesis can be defined as an "educated guess." For example, it might be an educated guess about why a natural event occurs. But not all hypotheses—even those about the natural world—are scientific hypotheses. What makes a statement a scientific hypothesis rather than just an educated guess? A scientific hypothesis must meet two criteria:
    ::假设一词可以被定义为“教育猜想 ” 。 比如,它可能是对自然事件为何发生的教育性的猜测。 但并非所有的假设 — — 甚至那些关于自然世界的假设 — — 都属于科学假设。 是什么使得一个说法成为一种科学假设,而不仅仅是一种教育猜想? 科学假设必须满足两个标准:

    • A scientific hypothesis must be testable.
      ::科学假设必须是可检验的。
    • A scientific hypothesis must be falsifiable.
      ::科学假设必须是可伪造的。

    A Scientific Hypothesis Must Be Testable
    ::科学假设必须是可检验的

    For a hypothesis to be testable means that it is possible to make that agree or disagree with it. If a hypothesis cannot be tested by making observations, it is not scientific. Consider this statement:
    ::如果无法通过观察检验一种假设,那么它就不是科学的。

    "There are invisible creatures all around us that we can never observe in any way."
    ::"我们周围有看不见的生物 我们永远无法观察"

    This statement may or may not be true, but it is not a scientific hypothesis. That’s because it can’t be tested. Given the nature of the hypothesis, there are no observations a scientist could make to test whether or not it is false.
    ::这种说法也许是真的,也可能不是真的,但它不是一个科学假设。 这是因为它不能被测试。 鉴于这一假设的性质,科学家无法做出任何观察来检验它是否虚假。

    A Scientific Hypothesis Must Be Falsifiable
    ::科学假说必须可以伪造

    A hypothesis may be testable, but even that isn’t enough for it to be a scientific hypothesis. In addition, it must be possible to show that the hypothesis is false if it really is false. Consider this statement:
    ::假设可能是可以检验的,但即使这样也不足以证明它是一个科学假设。 此外,如果假设是真的假的,必须能够证明假设是虚假的。 想想这个说法:

    “There are other planets in the universe where life exists.”
    ::“宇宙中还有其他行星存在生命。”

    This statement is testable. If it is true, it is at least theoretically possible to find evidence showing that it’s true. For example, a spacecraft could be sent from Earth to explore the universe and report back if it discovers an inhabited planet. If such a planet were found, it would prove the statement is true. However, the statement isn’t a scientific hypothesis. Why? If it is false, it’s not possible to show that it’s false. The spacecraft may never find an inhabited planet, but that doesn't necessarily mean there isn’t one. Given the vastness of the universe, we would never be able to check every planet for life!
    ::这个声明是可以检验的。 如果这是真的,至少理论上可以找到证据表明它是真的。 比如,如果发现一个有人居住的行星,航天器可以从地球被送去探索宇宙并报告。如果发现一个有人居住的行星,它就会证明这个声明是真实的。 但是,这个声明不是一个科学假设。为什么?如果它是假的,它不可能证明它是虚假的。航天器可能永远找不到一个有人居住的行星,但不一定意味着没有。鉴于宇宙的广度,我们永远无法检查每一个星球的生命。

    Both Testable and Falsifiable
    ::可测试和可伪造

    Let’s consider one last example, which is illustrated in the Figure :
    ::让我们考虑最后一个例子,

    "Any two objects dropped at the same time from the same height will reach the ground at the same time (assuming the absence of air resistance)."
    ::"同时从同一高度坠落的任何两个物体 将同时到达地面" (假设没有空气阻力)"

    Is this statement testable? Yes. You could drop two objects at the same time from the same height and observe when they reach the ground. Of course, you would have to drop the objects in the absence of air to prevent air , but at least such a test is theoretically possible. Is the statement falsifiable if it really is false? Again, the answer is yes. You can easily test many combinations of two objects and if any two objects do not reach the ground at the same time, then the hypothesis is false. If a hypothesis really is false, it should be relatively easy to disprove it.
    ::此语句是可测试的吗 ? 是的 。 您可以同时从同一高度投下两个对象, 并在它们到达地面时观察它们。 当然, 在没有空气的情况下, 您必须投下这两个对象来防止空气, 但至少这种测试在理论上是可能的 。 如果声明真的是假的, 该语句是否可以伪造? 答案是肯定的 。 您可以很容易地测试两个对象的许多组合, 如果两个对象没有同时到达地面, 那么假设是虚假的 。 如果假设是真的假说, 应该比较容易推翻它 。

    An elephant and a boy are shown falling, illustrating gravity's effect on both.
    Both the elephant and the boy are falling to the ground because of gravity. The force of gravity (Fgrav) is greater for the elephant than it is for the boy because the elephant is much more massive. Nonetheless, both of them will reach the ground at the same time (assuming they fall from the same height at the same time and there is no air resistance.)

    Can You Prove a Hypothesis Is True?
    ::你能证明一个假设是真实的吗?

    If the hypothesis above about falling objects really were false, it is likely that this would be discovered sooner or later after enough objects had been dropped. It takes just one exception to disprove a hypothesis. But what if the hypothesis really is true? Can this be demonstrated as well? No; it would require testing all possible combinations of objects to show that they always reach the ground at the same time. This is impossible. New objects are being made all the time that would have to be tested. It’s always possible an exception would be found in the future to disprove the hypothesis. Although you can’t prove conclusively that a hypothesis is true, the more evidence you gather in support of it, the more likely it is to be true. 
    ::如果上述关于坠落物体的假设真的是假的,那么,在有足够的物体被丢弃之后,这种假设很可能迟早会被发现。只要有一个例外就可以推翻一个假设。但如果假设是真实的呢?如果这个假设是真实的呢?能否证明这个假设是真实的?不;它需要测试所有可能的物体组合,以表明它们总是同时到达地面。这是不可能的。新物体在必须测试的所有时间里都会被制造出来。将来总是有可能发现一个例外来反驳这个假设。尽管你无法确凿地证明一个假设是真实的,但你为证明它而收集的证据越多,它就越有可能是真实的。

     

    Summary
    ::摘要

    • In science, a hypothesis is an educated guess that can be tested with observations and falsified if it really is false.
      ::在科学中,假设是一种有教育性的猜测,可以通过观察进行测试,如果真假的话,可以伪造。
    • You cannot prove conclusively that most hypotheses are true because it’s generally impossible to examine all possible cases for exceptions that would disprove them.
      ::你无法确凿地证明大多数假设都是真实的, 因为通常不可能审查所有可能的例外案例,

    Review
    ::回顾

    1. Identify the role of the hypothesis in science.
      ::确定假设在科学中的作用。
    2. State two criteria of a scientific hypothesis.
      ::提出科学假设的两个标准。
    3. Which of these two statements meets the criteria of a scientific hypothesis?
      1. Acids turn red litmus paper blue.
        ::酸会变成红色的 蓝色的树脂纸
      2. All life in the universe exists on Earth.
        ::宇宙中的所有生命都存在于地球上

      ::这两种说法中哪一种符合科学假设的标准? 酸会变成红色的柱状纸蓝色。宇宙中的所有生命都存在于地球上。
    4. Why is it usually impossible to prove that a hypothesis is true?
      ::为什么通常无法证明假设属实?

    Resources
    ::资源