Featured Image for a Blog Post: "A Darwinian Dilemma by Street"

Are you a moral realist ready to confront a provocative challenge? Read Sharon Street’s ‘A Darwinian Dilemma for Realist Theories of Value.’ This paper invites moral realists to ponder how evolutionary influences shape our moral judgments and the implications for the objectivity of moral truths. It is a thought-provoking read bound to stir debate and reflection.

Introduction to the Paper and the Author:

This is a paper published in 2006 by Sharon Street.

Sharon Street is a Philosophy Professor at New York University (as of September 2023)

Request the full article here: “A Darwinian Dilemma for Realist Theories of Value.”

The Aim of the Paper:

Sharon Street claims that evolutionary forces have had a major effect on the content of human evaluative attitudes. Moral realist theories, however, struggle to explain the link between these evolutionary pressures and the independent evaluative truths that they posit. The realist, in an attempt to provide an account, faces the Darwinian Dilemma. If realists argue that there is no connection between the two, this leads to a skeptical conclusion that most of our evaluative judgments can be inaccurate. On the other hand, she argues that the suggestion that natural selection has favored those who can grasp these truths is also problematic. Thus, realists cannot satisfactorily account for the relation between evolutionary pressures and independent evaluative truths. After laying out the Darwinian Dilemma against realists, she responds to three realists’ objections against the dilemma. Finally, Street will provide a positive account of how antirealist theories can overcome the dilemma.

What are Moral Realism and Anti-realism?

While natural and non-natural moral realism differ in their accounts, they believe some mind-independent moral truth or facts exist. Or, put in another way, they believe that some evaluative facts/truths hold true independently of our evaluative attitudes; thus, our evaluative attitudes cannot influence the truth. The natural moral realist holds that moral facts are natural facts. The non-natural moral realist holds that moral facts are not solely reducible to natural facts.

In contrast, anti-realism denies the above positions. Anti-realists could either reject the concept that moral properties exist or concede that they exist but contend that it is mind-dependent. There are many anti-realist positions, but I will not enumerate them here.

See Moral Realism and Moral Anti-Realism for more details.

What is the Core Idea of Natural Selection?

Evolutionary theory states that species do not evolve randomly but rather in response to their surroundings. An organism’s traits that are beneficial for survival in its surroundings will be the ones that are likely to be passed on by future generations; on the other hand, less advantageous features tend to go extinct. This is called natural selection, and it has influenced living creatures’ physical and behavioral properties.

Paper Reconstruction:

It is a long paper with much going on, so I will break the reconstruction into five parts.


Here is the premise: Evolutionary pressures have significantly influenced human evaluative attitudes.

Street defends the premise in section 4 of her paper but let us assume the premise is true in this post.

As Street warns us, natural selection is not the only factor that should be considered when attempting to understand the evolution of cognitive or physical traits. It is essential to recognize that numerous complex processes (e.g., genetic drift, social and cultural influence ) could lead to the emergence of various characteristics, which may be partially due to selection. However, she holds that natural selection has significantly influenced evaluative judgments.2

Two Horns of the Darwinian Dilemma Against Moral Realism3

The Darwinian Dilemma is posed by demanding an account of the connection between our evaluative judgments and independent moral truths, which the realists posit. In responding to the demand, Street argues that Moral Realists must make unattractive, implausible conclusions.

Let us consider the first horn of the Darwinian Dilemma. One can deny the relationship between evolutionary pressures and independent evaluative truths. Street argues that realists taking this path must accept the following: evolutionary pressures have had a distorting influence on our evaluative attitudes. If evolutionary forces have significantly influenced human evaluative attitudes (affirming the premise), it may have arbitrarily taken us away from independent evaluative truths.

Street provides a lucid analogy:

[The preceding view] analogous to setting out for Bermuda and letting the course of your boat be determined by the wind and tides: just as the push of the wind and tides on your boat has nothing to do with where you want to go.4

This indicates that if our evaluative attitudes and independent evaluative truths align, it must have done so by chance. But such an account by chance is unsatisfactory; there is no basis to believe that our evaluative attitudes and independent evaluative truths, in fact, align together. This skeptical conclusion leads to epistemically unjustified beliefs concerning moral beliefs, so she argues.

The second horn of the Darwinian Dilemma is to accept some relationship between evolutionary pressures and independent evaluative truths. The problem with this account is that independent evaluative truths (realist premise) lose their independence, arbitrarily determined by evolutionary pressures. According to Street, the tracking account attempts to mitigate the preceding concern by claiming that evolutionary influences on judgments align with independent evaluative truths because knowing the independent truth has been advantageous for rational beings’ survival and reproductive success. In other words, it is a claim that natural selection favors those capable of grasping moral truths.5

However, Street argues that an adaptive link account does a better job of explaining why we tend to make some evaluative judgments rather than others, making the tracking account inadequate for explanatory purposes. The adaptive link account says that our ancestors were more likely to have children and pass on their genes because they had certain ways of thinking and judging situations, not because they understood some universal truths. These ways of thinking helped them adapt to their environment and make decisions that were good for survival and having children. In other words, it was more about being practical and surviving in their world than knowing right or wrong. The adaptive account is parsimonious since it does not need to rely on an additional concept, independent truth, to explain differences in evaluative judgments. It is clearer than the tracking account because, concerning the tracking account, the connection between truth and reproductive success is obscure.6

If some species regard ‘infanticide laudable,’ it is unlikely that it survive over generations because it is likely to participate in infanticides. Therefore, we do not observe evaluative judgment like ‘infanticide is laudable.’ Species with certain attitudes or evaluative judgments ‘happen’ to survive over time, and the adaptive link account explains the absence of the preceding evaluative judgment; still, the tracking account fails to give a similar explanation.7

Response to the First Objection8

Suppose there are natural moral facts. A natural moral realist contends as follows: just as we have been successful in tracking dangers like fire and predators, we have been successful at tracking evaluative facts that are identical to natural facts. However, according to Street, the problem is distinguishing between evaluative and non-evaluative facts. Nicholas Sturgeon and David Brink’s approach to resolving the problem is constructing a moral theory that coheres with our evaluative judgments and the best empirical view of the world. Still, the method relies on evaluative judgments influenced by evolutionary pressure, posing the same Darwinian Dilemma discussed above.

Response to the Second Objection9

A realist may claim that the capacity of humans to understand objective evaluative truths might have been indirectly favored by natural selection as a byproduct or derivative of another capacity.10 For instance, the ability to do art or topology was not directly selected by natural selection but a byproduct of our capacity to perceive, imagine, and think abstractly. In response, Street asks: What is the connection, according to the realist, between the evolution of capacity C and the independent evaluative truths. Again, the realist may say there is a relation, or there is no relation. However, regarding some capacity C, this is the Two Horns of the Darwinian Dilemma discussed above.

Response to the Third Objection11

A realist will defend that pain is inherently bad regardless of our evaluative attitudes. If realists are correct, she successfully showcases that there is at least one independent moral truth. In response, Street begins with a definition of pain. According to her, a sensation counts as pain when an entity is unreflectively motivated to react to lessen that pain. She further expounds on her definition, but the details are unnecessary for this reconstruction. After discussing the definition, she argues that a realist faces a problem whether one accepts or rejects her definition (The Pain Dilemma). 

First Horn: Reject the definition.

The denial of Street’s definition of pain amounts to denying the necessary connection between the unreflective sensation and their reaction, counting in favor of whatever would avoid, lessen, or stop it. Since there is no necessary connection, an entity can be indifferent to the sensation or unreflectively favor whatever would increase or bring about the sensation. Thus, if realists reject the definition, it challenges the realism about pain’s inherent badness. In other words, there is an instance where pain can be evaluated positively or neutrally. 

Moreover, Streets argues evolutionary theory adequately explains why creatures perceive pain negatively: They merely associate pain with harmful bodily conditions. Realist relies on the tracking account, according to which we were selected to discern independent evaluative truth. But as seen in the Darwinian Dilemma argument, it does a poor job of explaining why we tend to make some evaluative judgments rather than others.

Second Horn: Accept the definition. 

Accepting Street’s definition amounts to regard pain as a sensation that a creature instinctively wants to avoid, lessen, or stop; thus, a creature will stop an action that causes pain. However, this acknowledgment leads to a crucial implication: the badness of pain depends on the creature’s unreflective evaluative attitude towards the sensation, meaning it depends on how the entity subjectively perceives and evaluates the pain.

The evaluative response of wanting to avoid or stop the pain is a significant factor in what makes the sensation ‘bad.’ Thus, the badness of pain depends on evaluative attitudes; it does not depend on independent moral facts, according to Street. 

Street’s Anti-realist View


A Critical Note:

Notes Pending…


  1. Sharon Street, “A Darwinian Dilemma for Realist Theories of Value,” Philosophical Studies 127, no. 1 (2006): 113-21. ↩︎
  2. Ibid.,113-14. ↩︎
  3. Ibid., 125-35 ↩︎
  4. Ibid., 121 ↩︎
  5. Ibid., 127 ↩︎
  6. Ibid., 129-30. Street challenges that the advocate of the tracking account must explain how independent truth, not truth simpliciter but normative truth, promotes reproductive success. ↩︎
  7. Ibid., 134. ↩︎
  8. Ibid., 135 – 41 ↩︎
  9. Ibid., 142 – 44 ↩︎
  10. Ibid., 142. ↩︎
  11. Ibid., 144 – 52. ↩︎

*Disclaimer: This article is a creative interpretation and synthesis work, drawing inspiration from multiple sources. While efforts have been made to ensure the accuracy of the information presented, readers are encouraged to consult the source material for a comprehensive understanding.

**Please note that I often write the Critical Note (constructive criticism) section after posting the article. If the section is left blank, it is intentional.

I use the term “Critical” in a broad academic sense, encompassing thorough examination, balanced evaluation, and thoughtful interpretation. It is not limited to pointing out flaws or offering negative criticism.

***I reserve the right to edit this page at my convenience.