相关背景及参考
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Andrej Karpathy - Academic Website | Blog | Github | Quora Session.
Research Scientist at OpenAI.
Previously ML/CV PhD student at Stanford under Prof. Fei-Fei Li.
Course Instructors for famous Stanford CS231n Course in Computer Vision. - [知乎] 博士这五年 @ 李沐.
近日，Open AI 人工智能研究科学家 Andrej Karpathy 完成在斯坦福的博士学位，其博士论文和他在博客上写的读博指导建议都获得了极大关注。
Andrej Karpathy：计算机科学博士的生存指南
- Karpathy原文参考：Andrej Karpathy's Blog : A Survival Guide to a PhD
- 机器之心译文参考：深度 | 李飞飞高徒 Andrej Karpathy：计算机科学博士的生存指南（附博士论文）
This guide is patterned after my “Doing well in your courses”, a post I wrote a long time ago on some of the tips/tricks I’ve developed during my undergrad. I’ve received nice comments about that guide, so in the same spirit, now that my PhD has come to an end I wanted to compile a similar retrospective document in hopes that it might be helpful to some. Unlike the undergraduate guide, this one was much more difficult to write because there is significantly more variation in how one can traverse the PhD experience. Therefore, many things are likely contentious and a good fraction will be specific to what I’m familiar with (Computer Science / Machine Learning / Computer Vision research). But disclaimers are boring, lets get to it!
如今，我即将完成自己的 PhD 学位，我想要写一篇文章回顾自己的经历，希望这对你们有一些帮助。不像本科指导，博士指导要更加难写，因为一个人如何完成自己的博士生涯相比本科有更多的变化。因此，很多事情可能是有争议的，我熟悉的一些部分（计算机科学/机器学习/计算机视觉研究）会具体写一下。
Preliminaries 预热
First, should you want to get a PhD? I was in a fortunate position of knowing since young age that I really wanted a PhD. Unfortunately it wasn’t for any very well-thought-through considerations: First, I really liked school and learning things and I wanted to learn as much as possible, and second, I really wanted to be like Gordon Freeman from the game Half-Life (who has a PhD from MIT in theoretical physics). I loved that game. But what if you’re more sensible in making your life’s decisions? Should you want to do a PhD? There’s a very nice Quora thread and in the summary of considerations that follows I’ll borrow/restate several from Justin/Ben/others there. I’ll assume that the second option you are considering is joining a medium-large company (which is likely most common). Ask yourself if you find the following properties appealing:
首先，你想要获得博士学位吗？在年轻的时候我就很幸运的明知我真的想要一个 PhD。不幸的是，我并没有经过深思熟虑：首先，我是真的喜欢学校和学习，我想尽可能多学一些东西。其次，我真的想成为游戏《半条命》里面的 Gordon Freeman 博士这样的人（从 MIT 获得理论物理博士学位）。我喜欢这个游戏。但在做人生决策时你更加敏感又会怎样？还会想要读 PhD 吗？（这里作者引用了自己在 Quora 上的回答，当时他在大公司的 offer 与读博之间做出的抉择。）我假设你正在考虑是否加入一个中型公司（大部分人都是如此），你可以问自己该公司是否有如下吸引力：
Freedom. A PhD will offer you a lot of freedom in the topics you wish to pursue and learn about. You’re in charge. Of course, you’ll have an adviser who will impose some constraints but in general you’ll have much more freedom than you might find elsewhere.
自由。读博在你想要追求和学习的主题上能提供很大的自由度。你在被别人管着。当然，读博也会有导师加以约束，但很大程度上要比其他更自由。
Ownership. The research you produce will be yours as an individual. Your accomplishments will have your name attached to them. In contrast, it is much more common to “blend in” inside a larger company. A common feeling here is becoming a “cog in a wheel”.
所有权。你做出的研究成果将会是你自己的，上面附属自己的名字。相反，在大公司内，「blend in」会很常见。常有的一个感觉是成为了「齿轮上的一个齿」。
Exclusivity. There are very few people who make it to the top PhD programs. You’d be joining a group of a few hundred distinguished individuals in contrast to a few tens of thousands (?) that will join some company.
排他性。很少有人单独成功做到顶级的博士项目。你将是加入一个由数百杰出个人组成的团队，相比于公司可能是数千人组成的团队。
**Status. **Regardless of whether it should be or not, working towards and eventually getting a PhD degree is culturally revered and recognized as an impressive achievement. You also get to be a Doctor; that’s awesome.
地位。不管是不是这样，向前进并最终获得博士学位在文化上是值得崇敬的，也是一项了不起的成就。你也将成为一个博士，这很棒。
Personal freedom. As a PhD student you’re your own boss. Want to sleep in today? Sure. Want to skip a day and go on a vacation? Sure. All that matters is your final output and no one will force you to clock in from 9am to 5pm. Of course, some advisers might be more or less flexible about it and some companies might be as well, but it’s a true first order statement.
个人自由。博士生是自己的老板。今天想睡觉？可以。今天想溜号休假？可以。所有的一切就是最后的博士成果，没人逼你要朝九晚五。当然，一些导师在这方面有很大的灵活性，一些公司也会灵活一些，但个人自由确实是初级声明。
Maximizing future choice. Joining a PhD program doesn’t close any doors or eliminate future employment/lifestyle options. You can go one way (PhD -> anywhere else) but not the other (anywhere else -> PhD -> academia/research; it is statistically less likely). Additionally (although this might be quite specific to applied ML), you’re strictly more hirable as a PhD graduate or even as a PhD dropout and many companies might be willing to put you in a more interesting position or with a higher starting salary. More generally, maximizing choice for the future you is a good heuristic to follow.
最大化未来的选择。加入博士项目并不是关闭了一些出路或减少了未来职业/生活方式的选择。你可以选择走一条路（PhD→其他），但并不只是一条路可走（其他→PhD→学术/研究）。此外（尽管应用机器学习专业相当特殊），博士毕业生甚至博士退学生更可能被雇佣，很多公司也愿意将你安排到更有趣的位置或给你更好的起始薪资。更广泛的说，最大化选择是你未来可以遵循的一个很具启发性的方法。
Maximizing variance. You’re young and there’s really no need to rush. Once you graduate from a PhD you can spend the next ~50 years of your life in some company. Opt for more variance in your experiences.
最大化你的转变。你还年轻，没必要这么着急进公司。一旦你从博士毕业接下来有 50 年的时间花费到公司。在你的人生经历中，选择有更多的转变。
Personal growth. PhD is an intense experience of rapid growth (you learn a lot) and personal self-discovery (you’ll become a master of managing your own psychology). PhD programs (especially if you can make it into a good one) also offer a high density of exceptionally bright people who will become your best friends forever.
个人成长。PhD 是一段快速成长（学到很多）和个人自我发现（成为掌握自我心理状态的大师）的浓重经历。PhD 项目（特别是如果你能成功进入一个好的项目）也能频繁的为你提供机会，交往一些格外阳光的朋友。
Expertise. PhD is probably your only opportunity in life to really drill deep into a topic and become a recognized leading expert in the world at something. You’re exploring the edge of our knowledge as a species, without the burden of lesser distractions or constraints. There’s something beautiful about that and if you disagree, it could be a sign that PhD is not for you.
专业性。PhD 可能是你人生中唯一的机会真的深入一个主题，并在某些事情上成为世界上处于领导地位的专家。在没有分心与约束的压力下，探索人类知识的边缘。这是一件非常美好的事，如果你不同意这一点，这可能就是一个你不适合读 PhD 的信号。
The disclaimer. I wanted to also add a few words on some of the potential downsides and failure modes. The PhD is a very specific kind of experience that deserves a large disclaimer. You will inevitably find yourself working very hard (especially before paper deadlines). You need to be okay with the suffering and have enough mental stamina and determination to deal with the pressure. At some points you will lose track of what day of the week it is and go on a diet of leftover food from the microkitchens. You’ll sit exhausted and alone in the lab on a beautiful, sunny Saturday scrolling through Facebook pictures of your friends having fun on exotic trips, paid for by their 5-10x larger salaries. You will have to throw away 3 months of your work while somehow keeping your mental health intact. You’ll struggle with the realization that months of your work were spent on a paper with a few citations while your friends do exciting startups with TechCrunch articles or push products to millions of people. You’ll experience identity crises during which you’ll question your life decisions and wonder what you’re doing with some of the best years of your life. As a result, you should be quite certain that you can thrive in an unstructured environment in the pursuit research and discovery for science. If you’re unsure you should lean slightly negative by default. Ideally you should consider getting a taste of research as an undergraduate on a summer research program before before you decide to commit. In fact, one of the primary reasons that research experience is so desirable during the PhD hiring process is not the research itself, but the fact that the student is more likely to know what they’re getting themselves into.
放弃。我也想说一下可能存在的消极面和失败模式。PhD 是一段非常特殊的经历，有大量的人会放弃。你将不可避免的发现自己做起来特别难（特别是该交论文之前）。你需要适应这些痛苦，并有足够的心理耐力和决心处理这些压力。有的时候你可能会过的不知道今天是周几，吃厨房的剩菜剩饭。在一个美妙的、阳光明媚的下午，翻动 Facebook 照片你发现朋友们拿着比自己多 5 到 10 倍的薪水享受着异国旅行，你要一个人坐在实验室精疲力尽。有时你会需要 3 个月的时间远离自己的研究，才能调整好健康的心态。在朋友们做着 TechCrunch 文章里面提到的创业时，或者在朋友们将产品推销给百万人时，你却挣扎着意识到几个月的研究花费到了一篇只有几个引用的论文上。你会经历自我认知的危机，怀疑生活中的抉择，想知道花费自己人生中最宝贵的时间正在做什么。最后，你应该相当确信，自己在追求科学研究与发现的路上，能够在无序的环境中成长、繁盛。如果你不确信，你会容易因是被而消极。在你决定读博之前，理想上你可以先在一个夏季研究项目上作为本科生尝试一下做研究。事实上，在 PhD 招聘期间，研究经验如此被看重的主要原因不是研究本身，而是博士生更知道自己正在做什么。
I should clarify explicitly that this post is not about convincing anyone to do a PhD, I’ve merely tried to enumerate some of the common considerations above. The majority of this post focuses on some tips/tricks for navigating the experience once if you decide to go for it (which we’ll see shortly, below).
我应该明确地澄清，这篇文章不是说服任何人去读博士，我只是试图枚举上面的一些常见的考虑。这篇文章的大部分重点是一些指导经验性的提示/技巧（我们将会在下文看到），如果你决定去读博。
Lastly, as a random thought I heard it said that you should only do a PhD if you want to go into academia. In light of all of the above I’d argue that a PhD has strong intrinsic value - it’s an end by itself, not just a means to some end (e.g. academic job).
最后，我想到有人说如果你想进入学术圈就读 PhD。基于上面提到的，我认为 PhD 有强大的固有价值，PhD 本身就是一个目的（end），而不只是达到某个目的（比如，学术圈的工作）方式。
Getting into a PhD program: references, references, references. Great, you’ve decided to go for it. Now how do you get into a good PhD program? The first order approximation is quite simple - by far most important component are strong reference letters. The ideal scenario is that a well-known professor writes you a letter along the lines of: “Blah is in top 5 of students I’ve ever worked with. She takes initiative, comes up with her own ideas, and gets them to work.” The worst letter is along the lines of: “Blah took my class. She did well.” A research publication under your belt from a summer research program is a very strong bonus, but not absolutely required provided you have strong letters. In particular note: grades are quite irrelevant but you generally don’t want them to be too low. This was not obvious to me as an undergrad and I spent a lot of energy on getting good grades. This time should have instead been directed towards research (or at the very least personal projects), as much and as early as possible, and if possible under supervision of multiple people (you’ll need 3+ letters!). As a last point, what won’t help you too much is pestering your potential advisers out of the blue. They are often incredibly busy people and if you try to approach them too aggressively in an effort to impress them somehow in conferences or over email this may agitate them.
进入一个博士项目：推荐、推荐、推荐。好，你决定努力争取一个项目，现在就是如何进入一个好的 PhD 项目？第一等级的逼近方式相当简单，目前最重要的就是强有力的推荐信。理想场景是一个知名教授这样为你写推荐信，「xx 是曾与我一起工作过的学而生中的前 5 名，她积极主动，有自己的想法，并付诸实践。」最差的推荐信就是，「xx 上了我的课，做的不错。」来自夏季研究项目的你自己的学术著作是一个强有力的加分，但并不如你有强有力的推荐信。特别提醒：分数并不强相关，但你一般不太想分数太低吧。本科时这在我身上并不明显，因为我花费大量精力取得好成绩。只有可能就直接与研究有关（或者最低限度就是与个人项目有关），尽可能的多，也尽可能的早，如果可能也要得到多人指导（你需要 3 个以上的推荐信！）最后一点，突然的纠缠未来可能成为你导师的人不会提供任何帮助。他们总是非常的忙，如果你想在回忆上或者通过邮件强势的接近他们，想要给他们深刻的印象，这可能反而会激怒他们。
Picking the school. Once you get into some PhD programs, how do you pick the school? It’s easy, join Stanford! Just kidding. More seriously, your dream school should 1) be a top school (not because it looks good on your resume/CV but because of feedback loops; top schools attract other top people, many of whom you will get to know and work with) 2) have a few potential advisers you would want to work with. I really do mean the “few” part - this is very important and provides a safety cushion for you if things don’t work out with your top choice for any one of hundreds of reasons - things in many cases outside of your control, e.g. your dream professor leaves, moves, or spontaneously disappears, and 3) be in a good environment physically. I don’t think new admits appreciate this enough: you will spend 5+ years of your really good years living near the school campus. Trust me, this is a long time and your life will consist of much more than just research.
选择学校。一旦你进入一些 PhD 项目，然后如何选择学校？很简单，斯坦福啊！开玩笑啦。严肃的说，梦想中的大学是首选（不是因为它看起来对你的履历/简历好，而是因为它的反馈环路。顶级学校也吸引其他顶尖人才，你可以跟其中的很多人相识、一起工作。）。第二就是有一些想要一起工作的导师。我说「一些」导师是很认真的，如果首选因各种原因无法达成，比如因理想教授离职、搬走或自然死亡而脱离了掌控，多一些导师选择对你而言很重要，也是一种安全保障。第三，选择一个好的物理环境，我认为新生不够注重这一点：你将花费生命中最好的 5 年时间生活在校园之中。相信我，这是相当长的时间，而且生命中不只有研究。
Adviser 导师
Student adviser relationship. The adviser is an extremely important person who will exercise a lot of influence over your PhD experience. It’s important to understand the nature of the relationship: the adviser-student relationship is a symbiosis; you have your own goals and want something out of your PhD, but they also have their own goals, constraints and they’re building their own career. Therefore, it is very helpful to understand your adviser’s incentive structures: how the tenure process works, how they are evaluated, how they get funding, how they fund you, what department politics they might be embedded in, how they win awards, how academia in general works and specifically how they gain recognition and respect of their colleagues. This alone will help you avoid or mitigate a large fraction of student-adviser friction points and allow you to plan appropriately. I also don’t want to make the relationship sound too much like a business transaction. The advisor-student relationship, more often that not, ends up developing into a lasting one, predicated on much more than just career advancement.
导师关系。导师是极其重要的人，会对你的博士生涯产生重要影响。理解这个关系的本质是很重要的：导师与学生之间是一种共生关系；你有自己的目标，想在博士阶段出些成果，但是导师也有他们的目标、约束，他们也要考虑自己的职业发展。因此，理解导师的激励机制是很有好处的，包括任职期间如何工作，这个职位的评估标准，他们如何获取经费，他们可能牵扯进了什么样的系内政治，他们如何拿奖，学术界通常是怎么运作的，还有尤其是他们如何获得认可和同事的尊重。这有助于避免或减轻与导师之间的摩擦并允许你进行适当的规划。我也不想让这种关系听上去更像是一种交易。导师与学生之间的关系不应该只是事业发展，而往往是一种持续的、可预测的关系。
Pre-vs-post tenure. Every adviser is different so it’s helpful to understand the axes of variations and their repercussions on your PhD experience. As one rule of thumb (and keep in mind there are many exceptions), it’s important to keep track of whether a potential adviser is pre-tenure or post-tenure. The younger faculty members will usually be around more (they are working hard to get tenure) and will usually be more low-level, have stronger opinions on what you should be working on, they’ll do math with you, pitch concrete ideas, or even look at (or contribute to) your code. This is a much more hands-on and possibly intense experience because the adviser will need a strong publication record to get tenure and they are incentivised to push you to work just as hard. In contrast, more senior faculty members may have larger labs and tend to have many other commitments (e.g. committees, talks, travel) other than research, which means that they can only afford to stay on a higher level of abstraction both in the area of their research and in the level of supervision for their students. To caricature, it’s a difference between “you’re missing a second term in that equation” and “you may want to read up more in this area, talk to this or that person, and sell your work this or that way”. In the latter case, the low-level advice can still come from the senior PhD students in the lab or the postdocs.
re-tenure 与 post-tenure。每位导师都不同，所以理解 tenure-track 的变化和他们对你博士生涯的影响也是很有帮助的。送上一条经验法则（记住也有很多例外），无论你的导师是处于 pre-tenure 还是 post-tenure，紧跟他的职业轨迹非常重要。通常情况下，年轻一些的教员常常比较多，级别也更低，但是他们也会对你的科研任务施加更强烈的建议，和你一起工作，抛出具体的想法，甚至会帮你检查代码（这是好事）。跟着这样的导师，更实际一些，课业也会更紧，因为他们需要发表很多质量不错的论文来获得 tenure，他们有动力推动你一样努力工作。相比之下，级别更高的教员或许有更大的实验室，除研究之外会有其他方面的优势（比如，委员会，讨论会，游学），这意味着，他们在学校里只能处在更高级别的职位，无论是在他们的研究领域，还是在监督学生上。讽刺的是，这就是「你在这个方程中漏掉了一个术语」和「你在这个领域还要多读些资料，和这个或那个人聊聊，这样或那样兜售你的成果」之间的区别。在后一种情况中，低水平的建议仍然来自于实验室里高年级博士研究生或者博士后。
Axes of variation. There are many other axes to be aware of. Some advisers are fluffy and some prefer to keep your relationship very professional. Some will try to exercise a lot of influence on the details of your work and some are much more hands off. Some will have a focus on specific models and their applications to various tasks while some will focus on tasks and more indifference towards any particular modeling approach. In terms of more managerial properties, some will meet you every week (or day!) multiple times and some you won’t see for months. Some advisers answer emails right away and some don’t answer email for a week (or ever, haha). Some advisers make demands about your work schedule (e.g. you better work long hours or weekends) and some won’t. Some advisers generously support their students with equipment and some think laptops or old computers are mostly fine. Some advisers will fund you to go to a conferences even if you don’t have a paper there and some won’t. Some advisers are entrepreneurial or applied and some lean more towards theoretical work. Some will let you do summer internships and some will consider internships just a distraction.
除了tenure 之外的其他变化。还有很多需要注意的变化。一些导师比较随意，另一些对待师生关系则比较专业谨慎。有些人会试图影响你的工作细节，有些则会放开手让你自己去做。一些会专注研究特定的几个模型及其在不同任务上的应用，而另一些则专注于任务不在意建模方法。从管理上看，有些导师能一周（或天！）见上几次，有些几个月都见不到人。一些导师会快速回复邮件，而另一些一周都不会回（甚至更长，哈哈）。一些导师会要求你给他一个时间表（比如，你最好能长时间工作或者周末工作）而另一些不会。一些导师慷慨地支持他们的学生，给学生配设备，还有一些认为有台笔记本或旧台式电脑就可以了。一些导师会资助你去参加会议，即使你没有投论文，有些则不会。一些导师是企业家类型的或者偏向应用，一些则更倾向于理论工作。一些会允许你暑期实习，另一些则认为实习会分心。
Finding an adviser. So how do you pick an adviser? The first stop, of course, is to talk to them in person. The student-adviser relationship is sometimes referred to as a marriage and you should make sure that there is a good fit. Of course, first you want to make sure that you can talk with them and that you get along personally, but it’s also important to get an idea of what area of “professor space” they occupy with respect to the aforementioned axes, and especially whether there is an intellectual resonance between the two of you in terms of the problems you are interested in. This can be just as important as their management style.
选导师。所以导师该怎么选呢？首先要和他们单独面谈。师生关系有时可以比喻成婚姻，要确保你们合得来。当然，首先你得确定你能和他聊天和他相处，不过相对于前述的 Tenure，要明白导师仍旧是教授，尤其是否能与你在你感兴趣的问题上产生智力共鸣。这比他们采取哪种管理方法更加重要。
Collecting references. You should also collect references on your potential adviser. One good strategy is to talk to their students. If you want to get actual information this shouldn’t be done in a very formal way or setting but in a relaxed environment or mood (e.g. a party). In many cases the students might still avoid saying bad things about the adviser if asked in a general manner, but they will usually answer truthfully when you ask specific questions, e.g. “how often do you meet?”, or “how hands on are they?”. Another strategy is to look at where their previous students ended up (you can usually find this on the website under an alumni section), which of course also statistically informs your own eventual outcome.
收集资料。你也应该收集一下心仪导师的资料。和他们的学生聊聊。如果你想得到有用的消息，这件事在正式场合下一定不能做，只能在轻松的场合（比如聚会）下问问未来的学长学姐。很多情况下，学生一般不会直接说导师不好，但是如果你问他具体的问题，他通常会真实的回答你，比如，你可以问「你们多久见一次面？」，或者「他现在有什么职务」。另一个策略是看看他之前带出来的学生最后都怎么样了（你可以在网站上找到），这样你就大概知道自己以后的去处了。
Impressing an adviser. The adviser-student matching process is sometimes compared to a marriage - you pick them but they also pick you. The ideal student from their perspective is someone with interest and passion, someone who doesn’t need too much hand-holding, and someone who takes initiative - who shows up a week later having done not just what the adviser suggested, but who went beyond it; improved on it in unexpected ways.
给导师留下印象。导师学生互选过程有时可以比喻成婚姻，你选他们，他们也选你。他们认为理想的学生是有兴趣有激情的，自律能力强，不需要手把手教，主动性强，一周内不仅能完成导师布置的任务还能自己有所拓展；用意外的方法改进结果。
Consider the entire lab. Another important point to realize is that you’ll be seeing your adviser maybe once a week but you’ll be seeing most of their students every single day in the lab and they will go on to become your closest friends. In most cases you will also end up collaborating with some of the senior PhD students or postdocs and they will play a role very similar to that of your adviser. The postdocs, in particular, are professors-in-training and they will likely be eager to work with you as they are trying to gain advising experience they can point to for their academic job search. Therefore, you want to make sure the entire group has people you can get along with, people you respect and who you can work with closely on research projects.
要考虑整个实验室。另一个重点是要意识到你会一周见导师一次，但是同门每天都能在实验室里见到，他们会成为你最亲密的朋友。在大多数情况下，你最后会与一些高年级博士生或博士后合作，他们的角色会非常类似你的导师。尤其是博士后，他们可能是未来的教授，他们也渴望和你一起工作，这样能积累带学生的经验。因此，你要确定整个团队中能有合得来的人，你尊重的人，还有你能亲密地做研究项目的人。
Research topics 研究主题
So you’ve entered a PhD program and found an adviser. Now what do you work on?
所以，如果你进入博士阶段，并找到一名导师。如何开展下去呢？
An exercise in the outer loop. First note the nature of the experience. A PhD is simultaneously a fun and frustrating experience because you’re constantly operating on a meta problem level. You’re not just solving problems - that’s merely the simple inner loop. You spend most of your time on the outer loop, figuring out what problems are worth solving and what problems are ripe for solving. You’re constantly imagining yourself solving hypothetical problems and asking yourself where that puts you, what it could unlock, or if anyone cares. If you’re like me this can sometimes drive you a little crazy because you’re spending long hours working on things and you’re not even sure if they are the correct things to work on or if a solution exists.
外围的锻炼。首先注意博士阶段的性质，一个博士学位读下来有苦有乐，因为你会不断接触到元问题（meta problem）。你不只是在解决问题——这仅仅是你要做的分内事。你的大部分时间要花在外围上，找出什么问题是值得解决的，什么问题已经成熟到可以解决。你要持续想象自己在解决假设问题，问自己处在什么位置，这个问题能打开什么，或者是否有人关心你研究的问题。如果你像我一样，就会有点疯狂，因为你在花大量的时间在做你甚至无法确定是否正确，也不知道能不能解决的事情。
Developing taste. When it comes to choosing problems you’ll hear academics talk about a mystical sense of “taste”. It’s a real thing. When you pitch a potential problem to your adviser you’ll either see their face contort, their eyes rolling, and their attention drift, or you’ll sense the excitement in their eyes as they contemplate the uncharted territory ripe for exploration. In that split second a lot happens: an evaluation of the problem’s importance, difficulty, its sexiness, its historical context (and possibly also its fit to their active grants). In other words, your adviser is likely to be a master of the outer loop and will have a highly developed sense of taste for problems. During your PhD you’ll get to acquire this sense yourself.
In particular, I think I had a terrible taste coming in to the PhD. I can see this from the notes I took in my early PhD years. A lot of the problems I was excited about at the time were in retrospect poorly conceived, intractable, or irrelevant. I’d like to think I refined the sense by the end through practice and apprenticeship.
Let me now try to serialize a few thoughts on what goes into this sense of taste, and what makes a problem interesting to work on.
研究品味。当你选择研究问题时，你会听到学术界讨一个神秘的概念「品味（taste）」。它一个实实在在的东西。当你向导师提出一个潜在的问题时，你可能会看到他们扭曲的脸，瞪大的眼睛，注意力飘忽的表情，或者当他们思考未知领域亟待探索时，你能感受到他眼神里的兴奋。在你抛出问题的瞬间发生很多事情：评价问题的重要性、难度、吸引力，它的历史语境（可能也会考虑是否能得到补助）。换句话说，你的导师是外围问题大师，在判断问题上品味很高。在博士阶段，你也会慢慢获得这方面的悟性。
我想过去我这方面的品味不太好，从我早期的博士笔记中就能看出来。当时令我兴奋的很多问题现在回想起来在构思上都不够精巧，难以下手，相关性也不强。经过实践和学习后，我的品味才得到提升。
我来试着总结一下关于怎样培养品味的思考，以及怎么让问题有趣地研究下去。
A fertile ground. First, recognize that during your PhD you will dive deeply into one area and your papers will very likely chain on top of each other to create a body of work (which becomes your thesis). Therefore, you should always be thinking several steps ahead when choosing a problem. It’s impossible to predict how things will unfold but you can often get a sense of how much room there could be for additional work.
一个丰饶的领域。首先，要意识到在你的博士阶段你会深入某个领域，你的论文很有可能进入研究链的顶端，自成体系（成为你的 thesis）。因此，选择一个问题时，你应该多往前思考几步。预测事情怎样进展不太可能，但是你能感知到你还有多大的研究空间。
Plays to your adviser’s interests and strengths. You will want to operate in the realm of your adviser’s interest. Some advisers may allow you to work on slightly tangential areas but you would not be taking full advantage of their knowledge and you are making them less likely to want to help you with your project or promote your work. For instance, (and this goes to my previous point of understanding your adviser’s job) every adviser has a “default talk” slide deck on their research that they give all the time and if your work can add new exciting cutting edge work slides to this deck then you’ll find them much more invested, helpful and involved in your research. Additionally, their talks will promote and publicize your work.
配合导师的研究兴趣和研究长处。你会想要直接进入导师研究兴趣的领域。一些导师或许会只允许你进入边缘地带，但是这样你就不能全部利用他们的知识，他们就不太可能想帮助你的项目或促进你的工作。例如，（这是我以前的想法）每位导师在研究上都有一个通用的幻灯片模板，如果你的研究成果够前沿，能被添加到那个幻灯片模板中，你就会发现导师对你的研究投入更多了，给你的帮助也多了。此外，他们还能帮助推广和公开你的成果。
Be ambitious: the sublinear scaling of hardness. People have a strange bug built into psychology: a 10x more important or impactful problem intuitively feels 10x harder (or 10x less likely) to achieve. This is a fallacy - in my experience a 10x more important problem is at most 2-3x harder to achieve. In fact, in some cases a 10x harder problem may be easier to achieve. How is this? It’s because thinking 10x forces you out of the box, to confront the real limitations of an approach, to think from first principles, to change the strategy completely, to innovate. If you aspire to improve something by 10% and work hard then you will. But if you aspire to improve it by 100% you are still quite likely to, but you will do it very differently.
要有点雄心：在努力这件事上要做到收放自如。人的心理都有个奇怪的 bug： 10 倍的重要或影响的问题在直观感觉解决起来就需要 10 倍的努力。这是个错觉——我的经验是 10 倍重要的问题，至多需要 2 到 3 倍的努力就行了。事实上，在一些情况下，一个 10 倍困难的问题解决起来可能更容易。为什么？因为你会有 10 倍的动力走出自己的黑箱，看到方法真正的局限性。从首要原理（first principles）开始思考，改变全部策略，继而创新。如果你渴望做出 10% 的改进并且很努力，你就会成功。但是如果你渴望做出 100% 的改进，你仍然很有可能成功，但会以一种非常不同的方式。
Ambitious but with an attack. At this point it’s also important to point out that there are plenty of important problems that don’t make great projects. I recommend reading You and Your Research by Richard Hamming, where this point is expanded on:
If you do not work on an important problem, it’s unlikely you’ll do important work. It’s perfectly obvious. Great scientists have thought through, in a careful way, a number of important problems in their field, and they keep an eye on wondering how to attack them. Let me warn you, `important problem’ must be phrased carefully. The three outstanding problems in physics, in a certain sense, were never worked on while I was at Bell Labs. By important I mean guaranteed a Nobel Prize and any sum of money you want to mention. We didn’t work on (1) time travel, (2) teleportation, and (3) antigravity. They are not important problems because we do not have an attack. It’s not the consequence that makes a problem important, it is that you have a reasonable attack. That is what makes a problem important.
雄心但也要能解决。在这一点上，需要指出的重要一点是有很多重要的问题无法做成大项目。我推荐阅读 Richard Hamming 写的一条博客：你与你的研究（You and Your Research），这里面探讨了这个问题：
如果你研究的问题不重要，你也就很有可能无法做出重要的成果。这是十分明显的。伟大的科学家会深思熟虑他们领域内的许多重要的问题，而且他们会密切关注、仔细琢磨如何攻克它们。让我警告你，「重要的问题」必须小心谨慎。当我在贝尔实验室的时候，物理学的三大突出问题在一定意义上都没有得到过研究。这里所说的「重要」是指肯定能得到诺贝尔奖和任何数量你想要的资金。我们不研究 1）时间旅行，2）物质传输，3）反重力。它们并不是不重要，而是因为我们无力解决。决定一个问题是否重要并不是因为结果，而是你可以合理地解决。这才是使一个问题重要的原因。
The person who did X. Ultimately, the goal of a PhD is to not only develop a deep expertise in a field but to also make your mark upon it. To steer it, shape it. The ideal scenario is that by the end of the PhD you own some part of an important area, preferably one that is also easy and fast to describe. You want people to say things like “she’s the person who did X”. If you can fill in a blank there you’ll be successful.
做到 X 的人。最后，PhD 的目标不只是成为某个领域内的深度专家，而且还要在这个领域打上你的烙印。要引导它，塑造它。理想的情况是：当你的 PhD 阶段结束时，你已经在一个重要领域赢得了自己的一席之地，最好是一个可以容易和快速地描述的领域。你想听到人们说「她就是那个做到 X 的人」这样的话。如果你能填补一项空白，你就是成功的。
Valuable skills. Recognize that during your PhD you will become an expert at the area of your choosing (as fun aside, note that [5 years]x[260 working days]x[8 hours per day] is 10,400 hours; if you believe Gladwell then a PhD is exactly the amount of time to become an expert). So imagine yourself 5 years later being a world expert in this area (the 10,000 hours will ensure that regardless of the academic impact of your work). Are these skills exciting or potentially valuable to your future endeavors?
有价值的技能。认识在到读博期间你将成为所选择的领域内的一名专家（撇开兴趣不谈，5 年×每年 260 个工作日×每天 8 个小时是 10,400 小时。如果你相信 Gladwell，PhD 正是需要大量的时间才能成为专家。）所以，想一下 5 年后你成为了这个领域的世界级专家（不论你的研究的学术影响，1 万小时将保证这一点。）拥有这些技能是不是很振奋？或者对你未来的职业足够有价值？
Negative examples. There are also some problems or types of papers that you ideally want to avoid. For instance, you’ll sometimes hear academics talk about “incremental work” (this is the worst adjective possible in academia). Incremental work is a paper that enhances something existing by making it more complex and gets 2% extra on some benchmark. The amusing thing about these papers is that they have a reasonably high chance of getting accepted (a reviewer can’t point to anything to kill them; they are also sometimes referred to as “cockroach papers”), so if you have a string of these papers accepted you can feel as though you’re being very productive, but in fact these papers won’t go on to be highly cited and you won’t go on to have a lot of impact on the field. Similarly, finding projects should ideally not include thoughts along the lines of “there’s this next logical step in the air that no one has done yet, let me do it”, or “this should be an easy poster”.
负面例子。也有一些难题或者论文类型你理想上想要避免。例如，有时你听到学习界讨论「增量工作（incremental work）」（这简直是学术界最糟糕的形容）。增量工作是指一篇论文通过使其更复杂并在一些基准上得到 2% 的额外增分，从而增强了一些已有的事情。这些论文的可笑之处在于有很高的机会会被接收（评审员没有拒绝这些论文的理由；有时它们也被称为 cockroach paper），所以你有这样的一系列论文被接受，你可以感觉自己非常高产，但事实上这些论文不会有很高的引用，你也不会在该领域有很高的影响力。类似的，寻找研究工程不能只理想的考虑「有这样一个下一步逻辑步骤还没有人做，让我来做」，或者「这应该是一个非常简单的 poster。」
Case study: my thesis. To make some of this discussion more concrete I wanted to use the example of how my own PhD unfolded. First, fun fact: my entire thesis is based on work I did in the last 1.5 years of my PhD. i.e. it took me quite a long time to wiggle around in the metaproblem space and find a problem that I felt very excited to work on (the other ~2 years I mostly meandered on 3D things (e.g. Kinect Fusion, 3D meshes, point cloud features) and video things). Then at one point in my 3rd year I randomly stopped by Richard Socher’s office on some Saturday at 2am. We had a chat about interesting problems and I realized that some of his work on images and language was in fact getting at something very interesting (of course, the area at the intersection of images and language goes back quite a lot further than Richard as well). I couldn’t quite see all the papers that would follow but it seemed heuristically very promising: it was highly fertile (a lot of unsolved problems, a lot of interesting possibilities on grounding descriptions to images), I felt that it was very cool and important, it was easy to explain, it seemed to be at the boundary of possible (Deep Learning has just started to work), the datasets had just started to become available (Flickr8K had just come out), it fit nicely into Fei-Fei’s interests and even if I were not successful I’d at least get lots of practice with optimizing interesting deep nets that I could reapply elsewhere. I had a strong feeling of a tsunami of checkmarks as everything clicked in place in my mind. I pitched this to Fei-Fei (my adviser) as an area to dive into the next day and, with relief, she enthusiastically approved, encouraged me, and would later go on to steer me within the space (e.g. Fei-Fei insisted that I do image to sentence generation while I was mostly content with ranking.). I’m happy with how things evolved from there. In short, I meandered around for 2 years stuck around the outer loop, finding something to dive into. Once it clicked for me what that was based on several heuristics, I dug in.
案例学习：我的主题。为了更详细的讨论这个话题，我打算使用自己如何展开 PhD 作为例子。首先，有趣的事实：我的整个主题都基于 PhD 期间一年半的研究。也就是，它花费了我相当长的时间在元问题空间（metaproblem space）不断摇摆，然后才找出了一个我感觉令我振奋的问题（其他两年我大部分是做 3D，比如 Kinect Fusion、3D 网、点云特征（point cloud features）、还有视频方面的工作）。然后在我读博第三年，在某个周六的下午两点，我来到了 Richard Socher 的办公室。我们闲聊时我意识到他在图像和语音上研究的一些问题事实上非常的有趣（当然，图像和语言交叉的这个领域在 Richard 之前就有了。）我难以看完所有需要查看的论文，但该领域看起来相当有前途：该领域相当的富饶（大量未解决的难题，在对图像进行基础描述尚有大量的可能性。）我认为这相当的酷，也很重要，也很简单去解释，看起来它处于成为可能的边缘（深度学习也只是刚开始有效），数据集也刚开始变得可用（Flickr8K 也刚出现）。这刚好满足李飞飞的兴趣，即使我没有成功，我至少得到了大量的时间，优化了我可能用于其他领域的有趣的深度网络。当所有事在我脑海中出现的时候，我强烈感觉到一股海啸。我把这个主题在第二天投给了导师李飞飞，感觉松了一口气。她热情澎湃地通过了，给予我鼓励。而且在接下来的工作中指导我，（例如，在我满足于排名的时候，飞飞坚持让我做图像语句生成。）后续的发展让我很高兴。简言之，我游荡了近两年才发现要深入的领域。给予数个启发方法，一旦我发现我要做什么，我就深入地去做。
Resistance. I’d like to also mention that your adviser is by no means infallible. I’ve witnessed and heard of many instances in which, in retrospect, the adviser made the wrong call. If you feel this way during your phd you should have the courage to sometimes ignore your adviser. Academia generally celebrates independent thinking but the response of your specific adviser can vary depending on circumstances. I’m aware of multiple cases where the bet worked out very well and I’ve also personally experienced cases where it did not. For instance, I disagreed strongly with some advice Andrew Ng gave me in my very first year. I ended up working on a problem he wasn’t very excited about and, surprise, he turned out to be very right and I wasted a few months. Win some lose some :)
阻力。我还想提一下你的导师绝不可能是一贯正确的。我已经见过或听说过很多实例了，现在回想起来，导师应该为错误负责。如果你在读博士时觉得导师错了，有时候你应该鼓起勇气忽略导师的看法。学术界普遍赞赏独立思考，但你特定导师的回应可能会随着环境发生变化。我就知道一些赌一把最后得到了很好结果的例子，而我个人也经历过一些效果并不好的例子。比如说，在我第一年的时候，我坚决不同意吴恩达给我的一些建议。我最后开始研究一个他并不非常感兴趣的问题，但让人惊讶的是，事实证明他是非常正确的，而我则浪费了几个月时间。吃一堑长一智嘛 :)
Don’t play the game. Finally, I’d like to challenge you to think of a PhD as more than just a sequence of papers. You’re not a paper writer. You’re a member of a research community and your goal is to push the field forward. Papers are one common way of doing that but I would encourage you to look beyond the established academic game. Think for yourself and from first principles. Do things others don’t do but should. Step off the treadmill that has been put before you. I tried to do some of this myself throughout my PhD. This blog is an example - it allows me communicate things that wouldn’t ordinarily go into papers. The ImageNet human reference experiments are an example - I felt strongly that it was important for the field to know the ballpark human accuracy on ILSVRC so I took a few weeks off and evaluated it. The academic search tools (e.g. arxiv-sanity) are an example - I felt continuously frustrated by the inefficiency of finding papers in the literature and I released and maintain the site in hopes that it can be useful to others. Teaching CS231n twice is an example - I put much more effort into it than is rationally advisable for a PhD student who should be doing research, but I felt that the field was held back if people couldn’t efficiently learn about the topic and enter. A lot of my PhD endeavors have likely come at a cost in standard academic metrics (e.g. h-index, or number of publications in top venues) but I did them anyway, I would do it the same way again, and here I am encouraging others to as well. To add a pitch of salt and wash down the ideology a bit, based on several past discussions with my friends and colleagues I know that this view is contentious and that many would disagree.
不要耍滑头。最后，我要让你认为 PhD 不只是一连串的论文。你不是一个论文写手。你是科研界的意愿，你的目标是推动该领域向前发展。论文是其中一种常见的做法，我建议你不要把目光放在已有的学术领域内。首先为自己想想，做一些其他人没有做但应该做的事，远离别人在你之前已经做出的成果。在我的整个 PhD 阶段我一直在尝试这么做。这个博客就是一个例子——这让我可以谈论一些通常不会发在论文里面的东西。ImageNet 人类推理实验就是一个例子——我强烈地认为，在 ILSVRC 上知道人类大致的准确度对该领域来说是非常重要的，所以我花了几周时间对其进行了评估。学术搜索工具（如 arxiv-sanity）也是一个例子——一直以来我都为论文文献搜索的低效性感到沮丧，所以我发布并维护了这个站点以便对他人有所帮助。两次参加 CS231n 教学也是一个例子——我在上面花了大量的精力，超过了一个应该做研究的博士生的合理程度，但我认为如果人们不能有效地学习这个主题和进入这一领域，这一领域的发展就会受到拖累。我的很多博士阶段的工作都很有可能会牺牲一些标准的学术指标（如 H 指数或在顶级会议上发表的数量），但我还是做了那些事情，我还会同样地再做那些事，在这里我也鼓励其他人也这么做。这可能言过其实了一点，除却思想观念上的一些东西，根据过去我与朋友和同事一些讨论，我知道这个观点是存在争议的，而且很多人也并不认同。
- 限于简书篇幅原因，下文请见：[中/英双语] Andrej Karpathy：A Survival Guide to a PhD （二）
（本文为自己整理学习收藏，译文部分参考机器之心翻译（有一段翻译漏掉了，自己加上去了，然后略作修改），在此表示感谢。未经允许禁止转载，授权转载请注明出处，谢谢！）
