On Earth Day 2022, US President Biden issued Executive Order 14072 (https://www.federalregister.gov/executive-order/14072), calling for – among other actions – an enduring definition of mature and old-growth forests. The assignment is not just an intellectual exercise. How forests are mapped in the mind will determine how forests are mapped on the ground, shaping both landscapes and policies. In their own work, ecologists and environmental scientists are called upon to define the terms that fundamentally shape how they perceive, describe, measure, and evaluate their worlds. Defining is consequently an important, foundational art for scientists, and it should be done well, with careful intentionality and critical self-awareness.

We – the authors of this commentary – are two professional philosophers who have spent careers teaching critical thinking, including the fine points and fallacies of definition in the ecological realm. Defining is a perilous art and there are many ways it can go wrong. Here, using the case of mature and old-growth forests, we offer some guidelines, and some warnings, for those engaged in defining terms within their work.

Resist writing a persuasive definition. There are many types of definitions. A lexical definition reports how a word is most commonly used, as dictionary-based definitions generally do. A stipulative definition declares that a certain word will be used in a certain way, which may or may not be its common usage. The risk comes when a stipulative definition becomes a persuasive definition – while purportedly describing the uncontested meaning of a term, in reality the definition stipulates a particular meaning to support an argument or action. That is a sort of logical bullying, assuming the power to settle the issue before it is even raised, as when Humpty Dumpty told Alice he could make a word mean whatever he wanted it to mean, depending on what served his purpose (Carroll L. 1865. Alice's Adventures in Wonderland. London: Macmillan & Co). This is a logical fallacy because it assumes what is in fact contested. An example is the definition of a “virgin” forest as one that has not been changed by humans – a persuasive definition that was used to justify removal of Indigenous people from forested lands.

Be aware of how hidden assumptions may already influence the defining process. The task assigned by Biden's Executive Order tacitly assumes that forests and forest products generally fall into the category of commodities – entities that can be traded for other human goods, such as money or building materials. Given that assumption, the task is to identify a category of forest that is so exceptionally valuable as a living entity that it should be preserved. It would offer quite a different assignment if the Executive Order assumed that, as a general rule, forests should be preserved. Then the challenge would be to identify the expendable forests – those that can be turned into job opportunities and human goods such as lumber.

Avoid defining a whole as the sum of its parts. It might be possible to define an old tree by age, height, basal area, canopy cover, and so forth. But a forest is not the sum or even the average of its trees. A forest has complexity, continuity, community, and other characteristics that a mere aggregation of trees does not. Moreover, it has complicated and impactful interactions with the communities around it, such that drawing definitional boundaries around a forest may be a mistake from the start. That said, it may be useful nonetheless to identify exceptional survivors, ancient trees that stand alone as champions of carbon sequestration or providers of essential habitat, as reminders of what has been lost around them, or even as testament to the possibility of human restraint.

Beware of the hegemony of numbers. Scientists, land managers, and others trained primarily in 20th-century Anglo-American traditions have been taught that empirically verifiable statements have privileged standing in making decisions. This may be why environmental scientists tend to default to numbers as descriptors. But some attributes that cannot be described by numbers are real and meaningful characteristics of forests. An obvious example is beauty. And some attributes that can be described by numbers are irrelevant to the definition. An example is the number of jobs that would be created by felling the trees. So, while having the advantage of allowing for comparisons across time and space, replication, manipulation by machines, etc, numerical descriptors carry the risk of distorting or entirely missing important characteristics of what is being defined. An enduring definition might use numbers, but it might be just as useful to use rubrics, stories, scenarios, ceremonies, and the arts.

Consider the diversity among forests themselves, as well as the pluralism of worldviews and perspectives of those interacting with them. Old forests come in a great variety. Any definition will be challenged to include forests as different from one another as temperate rainforests in the Pacific Northwest, longleaf pine (Pinus palustris) forests in the South, and hardwood forests in New England. There is diversity in the ages of a forest stand as well, and this can pose some quandaries. Is there such a thing as a potential old-growth forest, for example, as forests mature over time? Moreover, a definition will need to negotiate points of view as different from one another as extractive capitalism and Traditional Ecological Knowledge, the evolving knowledge acquired by Indigenous people through living in a place for millennia. Important differences exist within those worldviews as well. A core tenet of colonialism is the assumption that there is one privileged point of view, one true worldview, and one true religion (or forest management plan). A definition that escapes this assumption will make room for multiple understandings of the nature and worth of a forest.

If a definition refers to the value of a forest, keep in mind that forests have many values. Forests have instrumental values, of course: those functions that are valued because they serve human interests. Examples are sequestering carbon, cooling the air, shading salmon streams, and (through debt-for-nature swaps) paying off foreign debts. Not to be overlooked is an important set of instrumental values that we might call “affective” because they affect, or call forth a valued response in, the human heart. These might include feelings of awe, wonder, joy, mystery, kinship, and reverence. Complicating the picture are a forest's intrinsic values – values a forest has apart from its usefulness. These tend to be spiritual, moral, and aesthetic values. A forest doubtless has an ecology of productivity, but it also has an ecology of surprise and wonder, a rambunctious life-urgency, and a life-wisdom that includes instrumental, intrinsic, and affective values. Thus, an enduring definition will acknowledge multiple, complex, and interrelated values.

Be cognizant of the problematic nature of an enduring definition. It's likely that President Biden asked for a definition that “endures”, so that the issue does not have to be re-engaged every year, every election cycle, every level of the courts. But it is possible that an “enduring definition” is an oxymoron, a contradiction in terms. Our compressed view of time may allow us to think of forests as unchanging, but on every scale, old forests are in flux, as they face drought, wildfire, flood, “stand-replacement events” like clearcuts, and anthropogenic climate change. The political context of the forest is changing too, as people's views of forests evolve. In some circles, cutting old-growth trees – once an unquestioned practice – is, in the flash of only a few decades, becoming unthinkable. So, a definition of an old-growth forest that is fixed in time, however convenient that may be, is problematic in times of rapid change. Does that mean an enduring definition is impossible? Not necessarily. But it does mean that the process (note that “define” is a verb) will necessarily be characterized by humility, inclusivity, and imagination.

Attend to the nature of the defining process. Just as established uses may play a role in how forests are defined, established decision-making practices may play a role in the practice of defining. A common method of making decisions about forests is the stakeholder method, in which a group of people is assembled, each representing a particular set of interests – banks, landholders, fisherfolk, etc. (although note that the interests of the forest itself are seldom represented). Tribal leaders are often included as stakeholders, although that is a mistake of categorization, given that tribes are sovereign nations. The discussants hash it out, and often the decision favors the person with the most power, loudest voice, or strongest connection to entrenched interests. This is an unpromising way to write a definition (see persuasive definition, above). Here, the character of the people making the definition will be critical to its success. Are they dispassionate – caring, but even-handed? Are they honest? Is their thinking clear and inclusive? Can they imagine themselves in the position of the least powerful?

Be aware of your point of view. For obvious reasons, President Biden did not ask an old-growth forest to define an old-growth forest; forests are generally deemed to be inarticulate – although they communicate with one another, and they are certainly communicating to us in the languages of storm, plague, and fire. But just as it is presumptuous for one person to claim the right to define another, it is presumptuous to ignore the forest's point of view. Humans necessarily bring an anthropocentric perspective to the work of defining old growth. But we are creatures of imagination. With empathy and respect, we may ask: how would an old-growth forest define itself?

President Biden's request for a definition is important beyond words. Because it may quickly become a matter of which forests are preserved, it is quite literally a matter of life and death. And now, when old forests are sequestering substantial quantities of the carbon emitted by the global extractive economy, it might become a matter of the life and death of civilizations. How can we define mature and old-growth forests so empathetically, so expansively, so inclusively, so respectfully, that they – not merely their definition – can endure and by enduring, by breathing in and breathing out, help save us from the worst consequences of our mistakes?

在 2022 年地球日，美国总统拜登发布了第 14072 号行政命令 (https://www.federalregister.gov/executive-order/14072)，呼吁采取其他行动，对成熟森林和古老森林做出持久的定义。这项作业不仅仅是智力练习。森林在头脑中的映射方式将决定森林在地面上的映射方式，从而塑造景观和政策。在他们自己的工作中，生态学家和环境科学家被要求定义从根本上塑造他们如何感知、描述、测量和评估他们的世界的术语。因此，定义对于科学家来说是一门重要的基础艺术，应该以谨慎的意向性和批判性的自我意识来做好它。

我们——这篇评论的作者——是两位职业哲学家，他们的职业生涯都在教授批判性思维，包括生态领域定义的要点和谬误。定义是一门危险的艺术，有很多方式可能会出错。在这里，我们以成熟森林和古老森林为例，为那些在工作中定义术语的人提供一些指导方针和一些警告。

抵制写出有说服力的定义。定义有很多种类型。词汇定义报告单词最常用的方式，就像基于词典的定义通常所做的那样。规定性定义声明某个词将以某种方式使用，这可能是也可能不是其常见用法。当规定性定义成为有说服力的定义时，就会出现风险——虽然据称描述了术语无可争议的含义，但实际上该定义规定了支持论点或行动的特定含义。这是一种合乎逻辑的欺凌行为，在问题提出之前就假设有解决问题的权力，就像矮胖子告诉爱丽丝，他可以让一个词表达任何他想要的意思，这取决于他的目的是什么（Carroll L. 1865 年。《爱丽丝梦游仙境》。伦敦：Macmillan & Co）。这是一个逻辑谬误，因为它假设了实际上有争议的内容。一个例子是“原始”森林的定义是未被人类改变的森林——这是一个有说服力的定义，被用来证明将土著人民从林地中迁移出来是合理的。

请注意隐藏的假设可能已经如何影响定义过程。拜登行政命令分配的任务默认了森林和森林产品通常属于商品类别——可以用来交换其他人类商品（例如金钱或建筑材料）的实体。考虑到这一假设，我们的任务是确定一类森林，这种森林作为生物体具有极高的价值，因此应该得到保护。如果行政命令认为，作为一般规则，应该保护森林，那么这将带来完全不同的任务。接下来的挑战将是确定可消耗的森林——那些可以转化为就业机会和木材等人类物品的森林。

避免将整体定义为各部分的总和。可以通过年龄、高度、断面积、树冠覆盖度等来定义一棵老树。而是一片森林不是其树木的总和，甚至不是平均值。森林具有复杂性、连续性、群落性和其他单纯树木聚集所不具备的特征。此外，它与周围的社区有着复杂而有影响力的互动，因此在森林周围划定边界可能从一开始就是一个错误。尽管如此，识别特殊的幸存者、独立作为碳固存冠军或基本栖息地提供者的古树可能还是有用的，作为它们周围失去的东西的提醒，甚至作为人类克制可能性的证明。

谨防数字霸权。科学家、土地管理者和其他主要受过 20 世纪英美传统训练的人都被教导，可经验验证的陈述在决策中具有优先地位。这可能就是环境科学家倾向于默认使用数字作为描述符的原因。但有些无法用数字描述的属性却是森林真实且有意义的特征。一个明显的例子就是美丽。还有一些属性可以用数字来描述与定义无关。一个例子是砍伐树木将创造的就业机会数量。因此，虽然数字描述符具有允许跨时间和空间进行比较、复制、机器操作等优点，但它也存在扭曲或完全丢失所定义内容的重要特征的风险。一个持久的定义可能会使用数字，但使用标题、故事、场景、仪式和艺术也可能同样有用。

考虑森林本身的多样性，以及与森林互动的人们的世界观和观点的多元化。古老的森林种类繁多。任何定义都将面临挑战，将彼此不同的森林包括在太平洋西北地区的温带雨林、长叶松（Pinus palustris）中。）南部的森林和新英格兰的硬木森林。林分的年龄也存在差异，这可能会带来一些困境。是否存在潜在的古老森林，例如，森林随着时间的推移而成熟？此外，定义需要就采掘资本主义和传统生态知识等彼此不同的观点进行协商，传统生态知识是土著人民在一个地方生活了数千年而获得的不断发展的知识。内部存在重要差异那些世界观也是如此。殖民主义的核心原则是假设存在一种特权观点、一种真正的世界观和一种真正的宗教（或森林管理计划）。摆脱这一假设的定义将为对森林的性质和价值的多种理解腾出空间。

如果定义涉及森林的价值，请记住森林有很多价值。森林具有重要作用当然是价值观：那些因为服务于人类利益而受到重视的职能。例如封存碳、冷却空气、为鲑鱼溪流遮荫，以及（通过债务换自然）偿还外债。不容忽视的是一组重要的工具价值观，我们可以将其称为“情感”，因为它们影响人心，或在人心中引起有价值的反应。这些可能包括敬畏、惊奇、喜悦、神秘、亲情和崇敬的感觉。让情况变得复杂的是森林的内在价值——森林除了其有用性之外还具有的价值。这些往往是精神、道德和审美价值。森林无疑具有生产力的生态，但它也具有惊喜和奇迹的生态、喧闹的生命紧迫感以及包括工具、内在和情感价值的生活智慧。因此，

认识到持久定义的问题本质。拜登总统很可能要求一个“持久”的定义，这样这个问题就不必每年、每个选举周期、各级法院都重新讨论。但“持久的定义”可能是一种矛盾修辞，一种术语上的矛盾。我们对时间的压缩看法可能让我们认为森林是不变的，但在各个尺度上，古老的森林都在不断变化，因为它们面临着干旱、野火、洪水、砍伐等“林分更替事件”以及人为气候变化。随着人们对森林的看法不断变化，森林的政治背景也在发生变化。在某些圈子里，砍伐老树——曾经是一种无可争议的做法——在短短几十年的时间里，变得不可想象。因此，对原始森林的定义是固定的，无论多么方便，在快速变化的时代是有问题的。这是否意味着一个持久的定义是不可能的？不必要。但这确实意味着这个过程（注意“定义”是一个动词）必然具有谦逊、包容性和想象力的特征。

关注定义过程的本质。正如既定用途可能在森林定义中发挥作用一样，既定决策实践也可能在定义实践中发挥作用。制定森林决策的一种常见方法是利益相关者方法，其中聚集了一群人，每个人代表一组特定的利益——银行、土地所有者、渔民等（尽管请注意，森林本身的利益很少是代表）。部落领袖经常被列为利益相关者，尽管考虑到部落是主权国家，这是一个分类错误。讨论者们经过反复讨论，最终的决定往往有利于权力最大、声音最大或与既得利益关系最密切的人。这是一种没有希望的定义方式（参见上面的有说服力的定义）。这里，制定定义的人的性格对其成功至关重要。他们是否冷静、关心但不偏不倚？他们诚实吗？他们的想法是否清晰且包容？他们能想象自己处于最弱的地位吗？

注意你的观点。出于显而易见的原因，拜登总统并没有要求原始森林来定义原始森林；而是要求原始森林来定义原始森林。森林通常被认为是不善于表达的——尽管它们彼此交流，而且它们肯定用风暴、瘟疫和火灾的语言与我们交流。但正如一个人声称有权定义另一个人是自以为是一样，忽视森林的观点也是自以为是。人类必然会以人类为中心的视角来定义衰老的工作。但我们是想象力的生物。带着同理心和尊重，我们可能会问：古老的森林将如何定义自己？

拜登总统要求给出定义的重要性无法用语言来形容。因为这可能很快就会成为保护哪些森林的问题，所以这实际上是一个生死攸关的问题。现在，当古老的森林吸收了全球采掘经济排放的大量碳时，这可能会成为事关文明生死存亡的问题。我们如何才能如此富有同理心、如此广泛、如此包容、如此尊重地定义成熟森林和古老森林，使它们——不仅仅是它们的定义——能够持久，并通过持久、呼吸和呼气，帮助我们免受最坏的后果我们的错误？