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“It suddenly struck me that that tiny pea, pretty and blue, was the Earth. I put up my thumb and shut one eye, and my thumb blotted out the planet Earth. I didn't feel like a giant. I felt very, very small.” – Neil Armstrong (1930-2012)

Fresh Reads from the Science 'o sphere!

Sunday, January 13, 2008

Fact vs Theory

Just installed a new, easy-to-use Chinese input tool from Google. I haven't written a Chinese article for a long time, so here's a bilingual post for your reading pleasure. My apologies for awkward or inaccurate technical terms in Chinese; feel free to correct them in the comments section.

Fact versus Theory

Most people are too busy making a living to care about science. For them, science is a subject they learnt in secondary school that made them do gobs of meaningless calculations and memorize a ton of facts. Thus it is hardly surprising that they consider "fact" as the central essence of science. Facts appear to be solid, concrete things - permanent and dependable.

In contrast, the term "theory" is commonly used to describe a hunch, or at best an educated guess. Speculative and full of uncertainty. It isn't helpful that academic scientists use "theory" for something totally different - a highly-ranked class of solidly supported ideas that is far from speculative. This schism in semantics has been shrewdly capitalized during the Creation vs Evolution culture wars in the USA to portray evolutionary theory as an iffy conjecture.

Some people have proposed changing the term "theory" to "fact" to emphasize the certainty of biological evolution. While there are many facts that support it, evolutionary theory itself is not a fact, it is an explanation of facts. Thus I feel that switching these terms will simply cause more confusion.

Besides, by doing this they are reinforcing the public perception that facts are somehow more important than theories in science.

Are facts important? Of course! Without facts, the scientific endeavour would not be rooted in reality. Facts on their own constitute a significant compendium of human knowledge. In addition, you need accurate facts to help test and build a flourishing theory, or to help dismantle a failing theory.

Are theories important? Without a doubt! If not for theories, science would simply drown in an ocean of unconnected, isolated facts. Theories provide explanations for natural phenomena, and demonstrate meaningful relationships between the plethora of discovered facts. This allows us to apply our knowledge to other relevant scenarios and create new technologies. In addition, you need dependable theories to help check the reliability of the facts and guard against exaggeration or deliberate fraud.

So which one is the most important concept in science?

Actually, it is neither.

To me, the most important concept in science is the testable prediction.

Equipped with supporting evidence from facts and a explanatory framework from theories, we can then proceed to make precise, daring predictions.

Will there be an annular solar eclipse on the 7th of February, 2008 at 0355hrs Universal Time, most clearly visible from 67.6S latitude and 150.5W longitude? Will it last exactly 2 minutes and 12 seconds?

Will average density of the planetary bodies in our solar system decrease as their distances from the Sun increase? Will all the major bodies revolve around the Sun in the same direction?

Will there be a fossil that looks like a transition between a fish and an amphibian buried in a sedimentary rock layer that is 375 million years old?

Will homologous organisms, determined by comparative anatomy, also have highly similar genomic DNA sequences? Will closely-related species share evidence of viral infections that afflicted their last common ancestor?

The ability to generate precise, testable predictions and then trump them is the most impressive achievement of science. Toward this purpose, facts and theories are of equal weight - neither should be considered as mere conjecture or permanently cast in stone.

Thus, creationist and intelligent design "theories" that seek to deny many previously accumulated facts, do not provide a better explanation than existing theories, and do not or cannot in principle have any testable predictions - have no ability to generate any new knowledge. They are not scientific theories at all, not even hypotheses.

They are superstitions.

资料与理论

处在忙碌的生活里,多数人对于科学的兴趣不大。 对他们来说,科学是当年在中小学时读的一项科目,挤满了毫无意义的算术和堆积如山的事实资料。应此,人们难免会把“资料”当成科学的中心点。资料是固定的,可靠的。

相反的,“理论”在许多人的心目中只不过是一种悬空,暂时性的猜测。可惜科学家对于“理论”的用法持有天渊之别。唯有经历过严格实验证实的构思才能称得上是理论。在美国,这运用上的差异早已成为神创论者用来抨击演化论的工具。

为了强调演化论的实际性,有些学者认为演化的理论应该改称为一种“资料”。但是理论不是一种资料,它是一种解说大自然现况的方法。

对于科学来说, 到底是资料还是理论扮演比较重要的角色?

资料很重要吗? 当然! 没有资料的科学是不踏实的。玲琅满目的资料是人类整体智慧不可缺少的一部分。有了准确的资料,才能建立或反驳各种科学理论。

理论很重要吗? 毫无疑问! 没有理论的科学只能淹没在林玲种种的个例当中。理论把这些资料拼凑成一幅有意义的画。 有了明确的理论,科技才能迅速发展,而新发现的资料也能受到严格的评估,以防诈骗。

资料与理论各有千秋,但对我来说,科学最重要的力量,就是非常详细的推测。有了资料和理论并肩的支持,科学家能够做大胆的推测,有待实验证实。

下一次的日食会不会在2008年2月7日,UT凌晨3点55分发生? 日食会不会持续2分钟12秒?

太阳系里的行星平均浓度是不是越远离太阳越低? 该物体的轨道有没有一致的方向?

一个体型在于鱼类跟两栖动物之间的化石会不会出土? 它是不是埋在3亿7千5百万年前的石层里面?

体型接近的生物会不会也有类似的基因组脱氧核糖核酸次序?有共同祖先的生物有没有古代遗留下来的病菌踪迹?

准确的推测,是科学最令人叹为观止的成就。资料和理论的贡献不相上下, 也不容忽视。

相比之下,神创“论” 不理会大量的事实资料, 不比现有的演化论含有更高的解说价值,而且不能提供有意义的推测。一个不能测试的“理论”,连假定都不是。

它其实是一种迷信。

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2 Comments:

Daniel said...

Law > Theory > Hypothesis That's how I like to categorize them ;)
I probably put intelligent design somewhere in the hypothesis bracket.

Lim Leng Hiong said...

To Daniel:

Welcome to Fresh Brainz!

Actually "Laws" are not necessarily better or more accurate compared to "Theories". For example, Einstein's Theory of Relativity is more accurate than Newton's Law of Universal Gravitation.

So I would categorize them like this:

Law ~ Theory >> Hypothesis

As for intelligent design, it doesn't generate any testable predictions (since in principle an omni-everything deity can do whatever she wants) so it can't be a hypothesis.