这是一个常被提及大概念，或许是因为被Elon Musk多次提到。现在知识经济逻辑就是，把简单的概念复杂化，才显得自己专业和有价值，包括第一性原理。其实没那么玄乎，所谓大道至简。
这源于亚里士多德提出的一个哲学观点：每个系统中存在一个最基本的命题，它不能被替换或删除。指的是回归事物的最基本条件，将其拆分成 各要素进行结构分析，从而找到实现目标的最优路径。
也可以说按照这个逻辑，笛卡尔提出了Cogito，中文译 我思故我在。但这个如果用直译的汉语理解，就完全错了。笛卡尔提出 Cogito，源于他想找到恒定为真的事物，我们看到的听到的一切都可能是假的，都可以被怀疑。真正不能被怀疑的是我自己在思考这个事情。这是恒定为真的定义。
Wiki 的定义：
A first principle is a basic proposition or assumption that cannot be deduced from any other proposition or assumption. In philosophy, first principles are from First Cause[1] attitudes and taught by Aristotelians, and nuanced versions of first principles are referred to as postulates by Kantians.[2] In mathematics, first principles are referred to as axioms or postulates. In physics and other sciences, theoretical work is said to be from first principles, or ab initio, if it starts directly at the level of established science and does not make assumptions such as empirical model and parameter fitting. First principles thinking consists of deriving things to their fundamental proven axioms in the given arena, before reasoning up by asking which ones are relevant to the question at hand, then cross referencing conclusions based on chosen axioms and making sure conclusions don’t violate any fundamental laws. Physicists include counterintuitive concepts with reiteration.
ElonMusk的解读其实已经很通俗了：
I think people’s thinking process is too bound by convention or analogy to prior experiences. It’s rare that people try to think of something on a first principles basis. They’ll say, “We’ll do that because it’s always been done that way.” Or they’ll not do it because “Well, nobody’s ever done that, so it must not be good. But that’s just a ridiculous way to think. You have to build up the reasoning from the ground up—“from the first principles” is the phrase that’s used in physics. You look at the fundamentals and construct your reasoning from that, and then you see if you have a conclusion that works or doesn’t work, and it may or may not be different from what people have done in the past.[4]
I think it’s important to reason from first principles rather than by analogy. So the normal way we conduct our lives is, we reason by analogy. We are doing this because it’s like something else that was done, or it is like what other people are doing… with slight iterations on a theme. And it’s … mentally easier to reason by analogy rather than from first principles. First principles is kind of a physics way of looking at the world, and what that really means is, you … boil things down to the most fundamental truths and say, “okay, what are we sure is true?” … and then reason up from there. That takes a lot more mental energy.
Reason from first principles rather than by analogy
这是关键所在。
by analogy：是先看别人怎么做，对标公司怎么做，然后我再如何做。
Reason from first principles：把事情掰开揉碎，找到构成/影响事件的基本要素/逻辑，再思考最优路径
这是非常不同的两种思维方式。
爱因斯坦说过：如果我有一个小时来解决一个问题，我会先花50分钟来思考问题本身，然后用10分钟来思考解决方案。说的也是一回事儿。