Entrepreneurial action is fraught with uncertainty—investments must be made before revenues, and potential profits, have materialized, but after products and services have been designed, produced, and delivered. And yet, some of the leading theoretical frameworks in the entrepreneurship literature downplay uncertainty. Israel Kirzner's influential work depicts entrepreneurs as people who are particularly alert to future market conditions and who first “discover” opportunities for profit. Joseph Schumpeter's entrepreneurs engage in creative destruction, sweeping away old ways of doing business while introducing new products, new production and organizational methods, new markets, and so on. In these approaches, the entrepreneur knows what she wants and goes out and gets it.

Even if these approaches makes sense in “normal” times (which I do not believe), they do not seem to describe doing business in a world of rapid technological change, social disruption, economic volatility, or a major health crisis. The emergence of Covid‐19 in early 2020 brought radical, unanticipated economic, political, and social changes. In most parts of the world, schools, business, and workplaces were closed (voluntarily or involuntarily); people sheltered in their homes; and bankruptcies and unemployment soared. Governments and central banks announced unprecedented stimulus and subsidy packages but many companies large and small, operating with razor‐thin cash reserves, are struggling to survive.

How should entrepreneurs think, plan, and act in times of crisis? How do they handle unanticipated changes? To answer, it helps to think about how entrepreneurs deal with uncertainty more generally. My 2008 article “Opportunity Discovery, Entrepreneurial Action, and Economic Organization” proposes a reconceptualization of entrepreneurship not as the discovery of preexisting profit opportunities but as action under uncertainty. Frank Knight famously distinguished uncertainty from probabilistic risk. In a risky situation, I do not know what will happen next, but I know the set of possible outcomes and the likelihood of each, so I can use probabilistic reasoning to take the action that maximizes my expected gain (or, depending on my mood, that minimizes my expected loss). Under uncertainty, I cannot imagine even the set of possible outcomes, let alone the probabilities, so I must rely on intuition, gut feeling, or understanding to anticipate the uncertain future.

Knight used the term “judgment” to describe the act of decision‐making under uncertainty—that is, taking forward‐looking actions without the aid of a formal model or decision rule. My article builds on Knight's ideas to develop what Nicolai Foss and I have called a “judgment‐based approach” to entrepreneurship (Foss & Klein, 2012, 2020). This paper has stimulated new research on uncertainty, resource assembly, and governance—issues central to strategic entrepreneurship.

In a world of Knightian uncertainty, and heterogeneous capital resources with attributes that are subjectively perceived and unknowable ex ante, some agency must bear the responsibility of owning, controlling, deploying, and redeploying these resources in the service of consumer wants. That is the role of the entrepreneur—to combine and recombine heterogeneous capital resources in the pursuit of profit (and the avoidance of loss). When the entrepreneur is successful in acquiring resources at prices below their realized marginal revenue products—that is, when the entrepreneur exercises good judgment—she earns an economic profit. When her judgments are poor, she earns an economic loss. Competition among entrepreneurs (and those who provide financial capital to entrepreneurs) tends to steer ownership and control of productive resources toward those entrepreneurs with better judgment (Foss, Klein, Lien, Zellweger, & Zenger, 2020).

Good judgment is always at a premium, and even more so in a time of severe crisis. Consider the many sources of uncertainty entrepreneurs have dealt with in recent months. There is policy uncertainty: Can my business remain open, and under what conditions? What are the rules for social distancing, mask‐wearing, and cleaning for my workers, suppliers, and customers? There is demand uncertainty: Given the rapid economic contraction and surging unemployment, will customers be willing and able to buy, and under what circumstances? How should I alter my products and services, and should I introduce new ones to take advantage of current market conditions? I am uncertain about long‐term economic prospects, actions, and reactions of my rivals and partners; systemic changes in customer preferences; social and cultural norms for doing business; and much more.¹¹ In later work, Mark Packard, Brent Clark, and I distinguish between “absolute uncertainty,” “environmental uncertainty,” and “creative uncertainty” (Packard, Clark, & Klein, 2017), and there are other classification schemes out there as well.

Under these conditions, the usual set of quantitative forecasting tools are of little use. We need more and better research on heuristics, intuition, gut instinct, empathy, and other techniques of judgment, as well as processes of experimentation and learning that allow entrepreneurs to “test” their judgments in the market. Moreover, the laboratory of market competition likely works differently under extreme conditions. We know that firms respond differently to economic crises, with some even taking advantage of production slowdowns to invest in R&D, retraining, and reorganization (Klein, Knudsen, Lien, & Timmermans, 2020; Knudsen & Lien, 2015). Under what circumstances can skilled entrepreneurs take advantage of tough times?

The Covid‐19 crisis also highlights that entrepreneurship is about doing—assembling, reassembling, deploying, and even withholding valuable resources—rather than simply thinking. Entrepreneurs, if you like, are stewards, who hold the ultimate responsibility for determining how these resources will be used. The research and practitioner literatures celebrate successful entrepreneurship, such as introducing new products and services, creating new companies, or developing new business models, while describing retrenchments, consolidations, and bankruptcies as failures of entrepreneurship. But under uncertainty, like the kind experienced during a pandemic, someone must decide whether to keep going or change course, and that is a critical entrepreneurial function. Keeping a business closed, while others remain open, is also an entrepreneurial choice. We need more research on entrepreneurial decisions not to launch, not to innovate, not to expand as these decisions may represent the best use of valuable resources in difficult times.

Returning to uncertainty, I hope this crisis leads us, as a research community, to also think more deeply about entrepreneurship in “normal” times. While uncertainty, creativity, and the open‐endedness of entrepreneurial action are increasingly recognized and appreciated, the literature still imposes, in my view, an artificial distinction between “extraordinary” and “normal” conditions. But even in the absence of a pandemic or similar crisis, when facing incremental changes to known technologies in mature industries, uncertainty plays a role, and entrepreneurs have the responsibility of judging the future. In this sense, the crisis reinforces the arguments made in my 2008 article.

At the same time, the Covid‐19 crisis illustrates the limits of a general, theoretical framework like the one I offered in my article. Knowing that entrepreneurs bear uncertainty, and that successful entrepreneurs do it well, does not tell us exactly how those skills emerge, which individuals will have them, and how the competitive environment sorts between good and bad decisions. In this sense, the judgment‐based approach provides a starting point, but theoretical and empirical work is needed to flesh out the mechanisms, assign the magnitudes, and apply the analysis to the particular circumstances of time and place—like the extraordinary world of 2020.

创业行动充满不确定性-必须在实现收入和潜在利润之前，但在设计，生产和交付产品和服务之后进行投资。然而，企业家文学中的一些领先理论框架低估了不确定性。以色列·柯兹纳（Israel Kirzner）的有影响力的作品将企业家描绘成对未来的市场状况特别警惕并首先“发现”获利机会的人。约瑟夫·熊彼特（Joseph Schumpeter）的企业家从事创造性破坏活动，在引入新产品，新生产和组织方法，新市场等方面扫清了旧的经商方式。在这些方法中，企业家知道她想要什么，然后出去得到了。

即使这些方法在“正常”时期（我不相信）是有意义的，但它们似乎并没有描述在瞬息万变的技术变化，社会动荡，经济动荡或重大健康危机的世界中开展业务。2020年初Covid‐19的出现带来了根本性，出乎意料的经济，政治和社会变革。在世界上大多数地区，学校，企业和工作场所都被关闭（自愿或非自愿）；庇护所中的人们；破产和失业率飙升。各国政府和中央银行宣布了前所未有的刺激计划和补贴计划，但许多拥有稀薄现金储备的大小公司都在努力生存。

企业家在危机时期应如何思考，计划和采取行动？他们如何处理意料之外的变化？答案是，它有助于思考企业家如何更普遍地应对不确定性。我在2008年发表的文章《机会发现，企业家行为和经济组织》提出了企业家精神的重新概念化，不是发现既有的利润机会，而是将其视为不确定性下的行动。弗兰克·奈特（Frank Knight）著名地将不确定性与概率风险区分开来。在有风险的情况下，我不知道接下来会发生什么，但我知道可能的结果集和每种结果的可能性，因此我可以使用概率推理采取使我的预期收益最大化的操作（或取决于我的心情） ，从而将我的预期损失降到最低）。在不确定的情况下，我什至无法想象可能的结果集，

奈特使用“判断”一词来描述不确定性下的决策行为，即在没有正式模型或决策规则的情况下采取前瞻性行动。我的文章建立在骑士的想法，开发什么尼古拉福斯和我都被称为“基于判断的办法”，以创业（福斯和克莱因，2012，2020）。本文激发了有关不确定性，资源集合和治理的新研究，这些研究对于战略企业家精神至关重要。

在存在骑士式不确定性的世界中，且异质资本资源具有事先被主观感知和不可知的属性，某些机构必须承担拥有，控制，部署和重新部署这些资源以服务于消费者需求的责任。这就是企业家的角色，即在追求利润（以及避免损失）的过程中合并和重组异构资本资源。当企业家成功以低于其实际边际收入产品的价格获取资源时（即，企业家行使良好的判断力时），她将获得经济利益。当她的判断力很差时，她将蒙受经济损失。2020年）。

良好的判断力总是很重要的，在严重的危机时期尤其如此。考虑一下企业家最近几个月处理的许多不确定性来源。政策存在不确定性：我的业务可以在什么条件下保持开放？对我的工人，供应商和客户进行社交疏散，戴口罩和清洁的规则是什么？需求存在不确定性：鉴于快速的经济收缩和失业率飙升，客户是否愿意并有能力购买，在什么情况下？我应该如何更改我的产品和服务，并应该引入新的产品和服务以利用当前的市场条件？我不确定竞争对手和合作伙伴的长期经济前景，行动和反应；客户偏好的系统变化；开展业务的社会和文化规范；^1个1 在后来的工作中，马克·帕卡德（Mark Packard），布伦特·克拉克（Brent Clark）和我将“绝对不确定性”，“环境不确定性”和“创意不确定性”区分开（Packard，Clark和Klein， 2017年），还有其他分类方案，例如好。

在这种情况下，通常的定量预测工具集几乎没有用。我们需要对启发式，直觉，直觉，同理心和其他判断技术以及允许企业家在市场上“检验”其判断的实验和学习过程进行更多更好的研究。而且，在极端条件下，市场竞争实验室的工作方式可能会有所不同。我们知道，企业对经济危机的反应不同，有些企业甚至利用生产放缓来投资于研发，再培训和重组（Klein，Knudsen，Lien和Timmermans，2020年; Knudsen和Lien，2015年）。熟练的企业家在什么情况下可以利用艰难的时刻？

Covid-19危机还凸显了企业家精神是在做—组装，重组，部署甚至扣留宝贵的资源—而不是简单地思考。企业家（如果您愿意）是管理员，他们对确定如何使用这些资源负有最终责任。研究人员和从业人员文献赞扬成功的企业家精神，例如介绍新产品和服务，创建新公司或开发新的商业模式，同时将裁员，合并和破产描述为企业家精神的失败。但是在不确定的情况下，例如在大流行期间经历的那种，有人必须决定是继续前进还是改变路线，这是至关重要的企业家职能。在其他企业保持开放状态的同时，保持企业关闭也是企业家的选择。

回到不确定性，我希望这场危机能使我们作为一个研究团体，在“正常”时期也更加深入地思考企业家精神。尽管不确定性，创造力和企业家行为的开放性得到了越来越多的认可和赞赏，但在我看来，文献仍然在“非常规”条件与“正常”条件之间强加了人为的区分。但是，即使在没有大流行或类似危机的情况下，当成熟行业中的已知技术面临不断变化时，不确定性也起着作用，企业家有责任判断未来。从这个意义上讲，这场危机加强了我在2008年文章中提出的论点。

同时，Covid-19危机说明了一般性理论框架的局限性，例如我在本文中提供的框架。知道企业家有不确定性，成功的企业家做得很好，并不能告诉我们这些技能是如何产生的，哪些人会拥有这些技能，以及竞争环境如何在好决定和坏决定之间进行分类。从这个意义上说，基于判断的方法提供了一个起点，但是需要进行理论和实证研究来充实机制，分配数量级并将分析应用于特定的时间和地点，例如2020年的非凡世界。