Nancy Cartwright is part of the so-called Stanford School of philosophy of science and one of the most influential female philosophers. Rather than imposing a top-down, idealized view of science, this group focuses on real scientific discoveries and values scientific practice. Cartwright also considers herself an empiricist, but not in the traditional Humean sense, since she takes causation as undeniable in science. An important aspect of her philosophy of science is her emphasis on the particular over the universal. In particular, she argues against fundamentalism about the natural laws. Let’s see why.
Cartwright Says the World Is Too Untidy for Universal Laws
Cartwright takes the world to be dappled, and so science will inevitably be too. What Cartwright means by this is that the world is untidy, poorly organized, and only superficially regular.
Cartwright starts from the view that nature is Aristotelian rather than Humean, meaning a cause is an inner principle; things will follow their nature unless intervened upon. Like an electron being charged. It is in its nature to do/be so. Examining its nature explains the cause of the event it produces; they are grounds for causal explanation. Cartwright invokes this notion into her concept of capacities. Capacities are content-dependent and can be realized in multiple different ways. So they differ from concepts like essences or natural kinds—they are more about what things do.
Cartwright contends that most of what occurs in nature occurs by chance, subject to no inherent law at all. This seems at odds with naturalism and Humean empiricism, which base their metaphysics on natural law and the strong regularity of nature. Cartwright’s view rests on how she sees science achieving its success and its limitations.
While cosmological laws can be uniform and universal in the relative vacuum of space, they differ on Earth, where the world is significantly more dappled. Laws in Cartwright’s view are Aristotelian as well—the laws of science describe the powers that systems in nature have by virtue of certain facts about them.
Newton’s Law Only Explains Falling Objects in a Vacuum
To illustrate this, Cartwright challenges some of physics’ most fundamental laws and shows that, while laws may be simple, they must be modified to model the real world. She uses examples from modern science, such as Newton’s law of gravity and Maxwell’s equations (Cartwright 1983).
Newton’s law explains how an object falls in a vacuum, with no other causes operating on it. To treat it as a fundamental law of how objects fall seems like a misnomer to Cartwright, since it would not explain the motion of objects in most viable contexts. To describe how a 100-dollar note falls in Times Square, we would have to induce a model invoking all the different causes acting upon it.
While this could still be taken as a fundamental law operating on the 100-dollar note, one of many, Cartwright argues against this view. She treats these component forces as unreal, intrinsically unmeasurable, and unobservable. Instead, she treats them as component causal laws, not fundamental laws explaining the truth of the universe. They give a cause of motion, not the fundamental cause of motion.
Cartwright argues against fundamentalism, which holds that simple universal laws exist in the universe, are out there for our discovery, and best explain reality. So what physicists operate on is not fundamental laws, but models, approximations, and ad hoc corrections for causal disturbances. She takes physicists to be realists about causation but antirealists about theoretical explanations. This is shown by the fact that a phenomenon can incorporate several incompatible theoretical models, but scientists would never consider multiple incompatible causes or entities simultaneously.
In the Aristotelian sense, an explanation for a state must specify some feature or some object responsible for it. Fundamental laws circumvent this by positing a general, inherent characteristic of the universe. This is possible only because laws typically operate in highly idealized situations.
Cartwright Replaced Universal Laws With Nomological Machines
Instead of fundamental laws, Cartwright introduces the notion of nomological machines: setups of components with stable capacities, made by us or nature, that combine a relatively simple structure and shielding from outside influences to produce regularity.
Nomological machines can then be viewed as behaving as they do due to their natures (or causal capacities), which, in idealized situations, can invoke universal laws. Yet, these laws tend not to hold outside of these specialized contexts. These laws from idealized nomological machines do not instantiate universally, but at the level of component capacities; they are just part of the explanation.
This trends toward a disunified, pluralistic view of how to approach nature.
Pluralism is evident in actual science. Most fields and scientists operate on a patchwork network of connections between different levels of explanations. Science also operates on unreconciled theories in its models, in a similarly patchy way, reflecting the dappled nature of the world.
Fundamentalists would argue that we are moving toward a less dappled world, with more fundamental theories approaching a final theory. Cartwright takes this idea against the history of physics, in which more fundamental and universal theories become increasingly abstract and less applicable.
Cartwright Says Causation Can’t Be Reduced to Probability
A large part of Cartwright’s philosophy of science invokes causality, so it is important to take note of what she considers causality to be. While Cartwright argues that we need to accept genuine causal laws in nature, she shows they cannot be reduced to probabilistic notions, as traditional Humeans imply. She takes the difference between a causal relation and a spurious correlation to be the difference between causal laws.
The difficulty of inferring causal relationships from probability comes from the difference between causal relationships and spurious or confounding relations. The strongest link between probability and causal facts comes from the probabilistic relation between cause and effect across every subpopulation, holding everything else equal. This means we have to sift out or control for all causes of the effect.
We have to comb over all causes of the effect because otherwise a subpopulation may distort total population statistics with local/contextual causes. This does not mean the cause causes the effect; instead, a confounding factor could be at work. Cartwright’s example is that members of an academic insurance company have greater life expectancy than those who are not, yet this is also true for the academic subpopulation as a whole, contrary to the total population.
Randomized Controlled Trials (RCTs) Rule Out Confounders
The problem with statistical determination of causes is that you seemingly have to determine all the causes of the effect before you can determine it. The alternative is to rule them out with reasonable confidence, which is what Cartwright argues is what randomized controlled trials (RCTs) intend to do. Yet this limits their applicability, as idealized conditions are difficult to replicate outside highly controlled settings.
Randomization also does not guarantee that all relevant factors are balanced. RCT results are also only statistical and therefore lack meaningful causal explanations, making them harder to generalize without context. RCTs, like universal laws, can sin by treating an incredibly idealized context as representative of generality.
Because RCTs do not account for contextual factors beyond randomization, they can be confounded by such factors, limiting their applicability outside this subpopulation. Therefore, Cartwright argues against the trend of using RCTs as the panacea for all causal inferences.
Cartwright Says There Is No Single Concept Called ‘Cause’
But what does Cartwright actually contend to be causality then? She takes a pluralistic view: many different kinds of causes exist, and even causes of the same kind can operate in different ways. Different causal methods and accounts of causal laws typically fail to account for all causation because we often misconstrue it as a single monolithic concept, influenced by Kant and Hume.
Cartwright takes up the mantle of Anscombe (1971) and argues that causal law accounts of the typical character water down causal concepts—the generalized term “cause” replaces nomologically descriptive and rich causal verbs like poison, ignite, and push. These concepts imply causal relation but also give additional causal information.
Formalisms of causation are useful, particularly for scientific practice, but it is unlikely that they fit every system of laws. The world is too dappled for such a neat formal system. Different causal frameworks work well in specific use cases and when their assumptions are met, but not generally as frameworks for all that is considered causation.
Causal laws are useful for understanding intervention in the world, but they are not necessarily fundamental truths about reality. Rather, they are practical, context-dependent devices. Causal laws are relations as long as nothing intervenes.
Cartwright Says Chasing Fundamental Laws Wastes Scientific Resources
Cartwright argues against traditional Humeans, who deny causal laws and instead accept them as regularities of association, and against fundamentalists who attribute science’s success to the fundamental truth of the laws of physics. In a sense, in the search for what actually is the basis of the success of science, Cartwright takes it to be Aristotelian causal laws and capacities, not fundamental laws.
Cartwright has stated that her overall goal has been to study science for the betterment of society. She takes the goals of fundamentalism to be misguided, leading to resources being unevenly distributed to fundamentalist causes, which have limited practical implications. Examples are massively expensive particle colliders or genetic research in cancer. She does not deny the importance of either, yet more effective science may be pushed aside.
Cartwright argues that this focus stems from a misunderstanding of the world’s inherent nature and, by extension, science. In a dappled world, the obsession with fundamental laws makes little sense.
Sources
- Anscombe, G. E. M. (1971). Causality and Determination: An Inaugural Lecture. Cambridge University Press.
- Bovens, L., Hartmann, S., & Hoefer, C. (Eds.). (2008). Nancy Cartwright’s Philosophy of Science. Routledge.
- Cartwright, N. (1999). The Dappled World: A Study of the Boundaries of Science. Cambridge University Press.
- Cartwright, N. (1983). How the Laws of Physics Lie. Oxford University Press.
