In the landscape of contemporary ethical philosophy, Sharon Street stands out as a prominent figure, particularly known for her incisive critique of moral realism. Her seminal paper, “A Darwinian Dilemma for Realist Theories of Value,” has become a cornerstone in discussions surrounding metaethics and the influence of evolutionary theory on our understanding of morality. This article delves into Street’s argument, originally highlighted in a review of Thomas Nagel’s Mind and Cosmos, and presents a counter-perspective, questioning whether Street’s challenge to moral realism is as definitive as it may seem.
The initial exploration of Sharon Street’s work came as part of a broader reflection on Nagel’s philosophical positions. Nagel, in his work, leans on Street’s “Darwinian Dilemma” to argue against a purely naturalistic account of the cosmos. However, a closer examination of Street’s argument reveals potential weaknesses, suggesting that while her constructivist alternative to moral realism holds appeal, her rejection of moral realism itself might be premature.
This discussion will first outline Sharon Street’s “Darwinian Dilemma,” meticulously unpacking its core components. Following this, we will present objections to Street’s argument, challenging its premises and conclusions. While acknowledging the intellectual rigor of Street’s position and the attractiveness of constructivist approaches to ethics, this analysis aims to demonstrate that moral realism might withstand the Darwinian challenge more robustly than Street suggests.
Sharon Street’s Darwinian Dilemma: A Closer Look
Sharon Street’s “Darwinian Dilemma” centers on the assertion that natural selection, as a primary force shaping human cognition, presents a significant problem for moral realism. Moral realism, in essence, posits that moral truths exist independently of human opinions or beliefs. Street challenges this by arguing that if our evaluative judgments are significantly shaped by natural selection, then the alignment between these judgments and objective moral truths would be, at best, a mere coincidence.
Street begins by noting that natural selection operates on the “basic evaluative tendencies” of our ancestors. Even before the development of language and explicit moral reasoning, our predecessors possessed innate predispositions to perceive certain things as “counting in favor of” others. These rudimentary evaluations, shaped by evolutionary pressures, form the bedrock upon which our more sophisticated moral judgments are built. While acknowledging the influence of culture and other evolutionary factors like genetic drift, Street emphasizes the pervasive “evolutionary influence” on our entire system of evaluative judgments.
The crux of Sharon Street’s dilemma lies in the nature of natural selection’s influence. She argues that natural selection is “purely distorting” concerning evaluative judgments. It selects for tendencies based on their adaptiveness – their contribution to survival and reproduction – not their capacity to track objective moral truths. This contrasts sharply with perceptual judgments. For instance, the accuracy of perceiving a nearby fire is directly linked to survival, making accuracy adaptive in this domain.
However, Street contends, the same cannot be said for moral judgments. Consider the judgment “caring for offspring is good.” While the tendency to care for offspring is undeniably adaptive, the accuracy of the judgment itself, its correspondence to an objective moral truth, is not what natural selection targets. Even if, hypothetically, caring for offspring were objectively “bad,” the adaptive advantage of the tendency would remain unaffected, and the “inaccuracy” of our moral judgment would have no negative evolutionary consequences. Thus, Street argues, it would be an extraordinary and improbable coincidence if natural selection, acting solely on adaptiveness, happened to mold our evaluative tendencies in a way that reliably tracks objective moral truths.
Street anticipates an objection: perhaps our capacity to grasp evaluative truths is a non-adaptive byproduct of a more fundamental cognitive ability that is shaped by natural selection. This is analogous to how our capacity for astrophysics is likely a byproduct of general cognitive abilities selected for other reasons. However, Street insists that for this byproduct argument to work, the underlying basic capacity must be non-evaluative. If the foundational capacity itself were evaluative and shaped by natural selection, it would inherit the “distorting” influence, undermining any claim to objective moral truth.
Furthermore, Sharon Street argues that our evaluative abilities are “highly specialized” and “specifically attuned” to particular evaluative truths. Drawing an analogy to the human eye, she suggests that the complexity and functional specificity of our moral reasoning capacities cannot be explained as a mere byproduct of some unrelated, non-evaluative capacity. This leads her to conclude that moral realism is fundamentally incompatible with the Darwinian understanding of human origins.
For Street, this incompatibility does not imply that all evaluative claims are meaningless or arbitrary. Instead, she advocates for an anti-realist perspective, suggesting that moral truths are contingent upon our own evaluative attitudes and cognitive constitution. This view aligns with constructivism, where the truth of a moral judgment is determined by its coherence within a system of reflectively endorsed beliefs and attitudes – a “reflective equilibrium.” In this framework, evaluative truth emerges from the internal consistency and mutual support among the evaluative judgments shaped by evolutionary pressures and further refined through rational scrutiny.
Objections to Street’s Darwinian Dilemma and the Case for Domain-General Cognition
While Sharon Street’s “Darwinian Dilemma” presents a compelling challenge to moral realism, it is not without its critics. One key area of contention lies in Street’s assumption about the functional specificity of our cognitive and evaluative capacities. Her argument hinges on the idea that these capacities are as finely tuned and specialized as the human eye, directly shaped by natural selection for specific purposes. However, this assumption is debatable and connects to broader discussions about the modularity of the mind.
The concept of modularity of mind proposes that the mind is composed of distinct modules, each dedicated to specific functions and shaped by natural selection for those particular tasks. Massive modularity, an even stronger claim, suggests that all mental functions, including higher-level cognitive abilities, are modular. However, both modularity and massive modularity are contested theories. Critics argue that the brain may have evolved to be a more general-purpose problem-solving organ, rather than a collection of highly specialized modules.
Instead of being narrowly specialized, the brain might have evolved to be highly adaptive to diverse and changing environments. This adaptability could stem from “domain-general” capacities – cognitive abilities that are not specific to particular tasks but can be applied across various domains. Capacities like reasoning, planning, and problem-solving, which underpin complex activities like mathematics and philosophy, could be examples of such domain-general abilities. It’s plausible that our capacity for evaluative judgment, rather than being a specialized module shaped for tracking moral truths, is also a byproduct of these more general cognitive capacities, intimately linked to our ability to reason and make sense of the world.
The moral realist, in this context, can argue that evaluative judgments, like other forms of judgment, can be true or false. A cognitive system that is generally sensitive to truth and falsity, even if not specifically designed for moral truth-tracking, might nevertheless be capable of discerning moral truths. Just as scientific inquiry allows us to explore novel domains and uncover truths about the physical world using general cognitive tools, so too might our general reasoning abilities enable us to access moral truths, regardless of whether evolution specifically tailored these abilities for that purpose.
Street argues that truth and adaptiveness align in basic perceptual judgments, allowing our cognitive capacities to model the world effectively, implicitly acknowledging some level of domain-generality. However, she then demands a much higher degree of functional specificity for evaluative judgments and sets stringent criteria for the relatedness between evaluative capacities and any underlying, more general capacities. This demand for such a high level of specificity seems inconsistent with what we understand about the domain-general nature of human cognition. As Street herself acknowledges, evolutionary theorizing often errs by assuming that every trait is a direct adaptation, overlooking the possibility of byproducts and other complex, non-selective evolutionary processes. It appears she might be falling into a similar trap by insisting on a level of functional specificity for cognitive traits that may not exist.
Even if our capacity for veridical evaluative judgments is a byproduct of more general cognitive abilities, it’s likely that these judgments will often intersect with the selection-pressured evaluative tendencies Sharon Street describes. The key point is that there could be an additional layer – a capacity for reflection and critical evaluation that goes beyond simply reconciling existing tendencies in reflective equilibrium. This capacity might allow us to critique our evolved tendencies in light of what is really “good” and “bad,” appealing to a more objective standard than mere coherence within our existing belief system.
This is not to dismiss the challenge natural selection poses to moral realism entirely. Street’s “coincidence objection” retains some force. For moral realism to be fully convincing in the face of evolutionary considerations, it needs to address one of two points: either demonstrate that at least some evaluative judgments are not simply products of evolutionarily shaped tendencies (or are demonstrably inconsistent with reflective equilibrium reached solely through these tendencies), or explain why evolutionarily advantageous tendencies would reliably align with a capacity for evaluative judgment that is supposedly unrelated to those tendencies – what Street terms “tracking.”
One avenue for the moral realist is to argue that adaptiveness and objective goodness are systematically linked, such that evolutionary pressures would, in fact, tend to favor tendencies that lead to true evaluative judgments. However, this path might inadvertently lead back towards a constructivist account, where “goodness” becomes relative to the constitution and flourishing of organisms.
Conclusion: Moral Realism and the Darwinian Challenge
In conclusion, while Sharon Street’s “Darwinian Dilemma” offers a potent critique of moral realism, it is not without its weaknesses. The objection grounded in the domain-general nature of cognition and the possibility of evaluative judgment as a byproduct of broader reasoning capacities casts doubt on the definitive nature of Street’s challenge. While the appeal of constructivist accounts of morality remains strong, and Sharon Street’s work significantly enriches our understanding of metaethical debates, it appears premature to conclude that she has definitively demonstrated the incompatibility of moral realism and natural selection. The debate continues, and the intricate relationship between evolution, ethics, and the nature of moral truth remains a vibrant and crucial area of philosophical inquiry.
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