Can Science Inform You About What You Should Do?

Do science and morality conflict?

Posted Mar 29, 2020

Can science guide morality?

For some decades, moral philosophers have turned a jaundiced eye toward “facts,” not allowing direct bearing on moral judgments. They point out that a fact should not motivate a corresponding value.

I have experienced the dismissal. For example, when I have presented scientific facts about the importance of affectionately (respectfully) touching your child, one male philosopher called me a Nazi and said he did not want to have to touch his children. When I presented at another conference about the evolved nest and its known effects, I described how breastfeeding builds a healthy brain and body. During the discussion period, a female philosopher berated me for advocating breastfeeding, arguing with me into the coffee hour afterward (I inferred that she had not breastfed her children).

These philosophers were arguing that just because there is scientific evidence for the benefits of something, it doesn’t mean we should do it. They were upholding what they considered the fact/value distinction, a common concern of moral philosophers today.

The best explanation of the fact/value distinction I have found was written by J. Baird Callicott.

Callicott notes that G.E. Moore (1903) was confused himself about what he meant by the term, but for sure Moore was arguing against the utilitarians who contended that what was pleasurable was good: “To claim that the property of being pleasurable or being pleasure-producing is what makes good things good (intrinsically or instrumentally, respectively) is to commit the Naturalistic Fallacy” (p. 71).

Moore argued that what is pleasant is not necessarily good or moral. The good and the pleasant cannot be the same.

  • Moore’s view of the Naturalistic Fallacy: Pleasure = Good

But this is not a formal fallacy of logic. Another related topic, the Is/Ought Dichotomy, is a fallacy.

The Is/Ought Dichotomy, attributed to David Hume who wrote about it in passing, proposes that declarative (“is”) and imperative (“should”) statements are logically different. Moral philosophers have taken Hume to mean that one cannot take a fact and derive a “should” or “ought,” leading to many philosophers dismissing scientific facts as having no bearing on moral judgment or action—as I found in the separate incidents described above.

  • Hume’s view of the Is/Ought Fallacy: Fact [is] = Value [ought]

Alaisdair MacIntyre dismissed the Is/Ought Fallacy in the way that most philosophers understand it. He explained that Hume was pointing to a missing link between statements of fact and statements of value. One did not follow from the other logically. Hume filled the gap with feeling. That is, subjective feelings provide the logical link between statements of fact and statements of value. As MacIntyre (1969, p. 48) writes: “Hume is not…trying to say that morality lacks a basis; he is trying to point out the nature of that basis”—feelings.

  • Hume: Facts —> Feeling —> Value

But then, according to Callicott, philosophers confuse Hume with Kant’s move.

Immanuel Kant, famous for his categorical imperative (act in a way that you would support it becoming a universal law), does infer “should” statements from is-statements. He expresses them as hypothetical imperatives. “If” is the hypothetical and “then” is the imperative (command). Here are two kinds of imperatives he uses:

The “problematical” of skill:

  • If [you want to be a concert pianist], then [you should study with a master teacher].

The “assertorical” of prudence:

  • If you want to be healthy, then refrain from smoking tobacco.

Analytically, the if-statement [desire statement] and the ought-statement [the means to achieve the desire] have the strongest of all possible logical links.

In terms of our moral judgments and actions, we can take the If-Then hypothetical imperatives of Kant’s design and apply them to our lives. For example:

  • If you want compassion to prevail —> then start with your own self-compassion.

Kant disregards Hume’s ethical theory (of feelings being important to morality) as practical anthropology (Callicott, p. 76), and goes on to base his categorical imperative not on facts, feeling, or personal interests, but in reason.

  • Kant: Reason —> value imperative [moral ought]

When moral philosophers take Kant’s move as Hume’s and attribute moral imperatives to be only rooted in reason, they are misunderstanding Hume and the issue at hand. For Hume, reason does not move us; only feeling does. But feeling does rely on facts. So it matters which facts a person takes to be true.

MacIntyre (1969) points out that Hume thought that “if all factual disagreements were resolved, no moral disagreements would remain” (p. 48). To resolve differences in moral judgment, reason must be used to ascertain general facts, causal relations, drawing conclusions from comparing familiar and novel situations, and making fine distinctions. Then people would have the same feelings and judgments. To be clear:

  • Hume: Facts (determined by Reason) —> Feeling —> value imperative [ought]

Environmental philosopher, J. Baird Callicott (2013) integrates these ideas with those of Aldo Leopold’s land ethic. On the other side of the equation, Leopold admonished scientists for believing that ecological science had no relation to right and wrong (Leopold, 1991, p. 183). Leopold noted that when the European/American settlers applied the conventional pastoral methods (of European origin) to the land in the Southwest, it was disastrous, wrecking the land.

“He drew the fine distinction that what is land-ethically permissible in one place—livestock grazing in Western Europe and in Eastern North American—is land-ethically impermissible in another place, the American Southwest” (p. 80).

Leopold’s example shows the intersection of facts and values. Facts truly matter: If we want a landscape to thrive, then we have to learn what it needs and how to provide it. Values also matter. To treat the landscape in a manner that helps it thrive, we must take up the moral responsibility to do so. For native peoples around the world, generations of observation taught them how best to treat the land, animals, plants with respectful care. So there are two aspects Leopold uncovered:

  • If you want a landscape to thrive —>  learn its needs and meet them (a mix of fact and value)

What Callicott and Leopold do not explain here is Hume’s logical link of feeling. But others have done so. Wendell Berry, poet and eco-activist, jolted the world with his observation that after decades of agreeing about the importance of ecological conservation, reasoning and argumentation were not working to motivate action. Reason alone had not led to thriving ecologies. He concluded, “It all turns on affection” (Berry, 2013). We must feel empathy, sympathy, interdependence, and love for the natural world, and those feelings will motivate our actions to preserve its health, biodiversity, and beauty.

We can apply these ideas to my experiences discussing the evolved nest with philosophers: Reason (factual information) alone was not enough to persuade them about the actions to take in the best interest of babies and young children. People also must believe the facts.

I think the philosophers I mentioned did not believe the facts I presented, likely because they were contrary to their culture-based views.

Believing the facts about the environment, as ecologically-concerned folks do, is also not enough for action. People must also feel bonded to the object of attention and make it an object of their affection. Whether landscapes or children, an individual must understand that his wellbeing is intertwined with theirs. But they must also care about that interdependence (of course, an individual must also feel care for herself to be able to feel care for others). One must care-for, not only care-about in a relational manner (Noddings, 2010).

There are many steps from knowledge (reason, facts) to action, such as:

  1. Learn the facts. (reason)
  2. Believe the facts. (reason)
  3. Feel care for (self and) the other. (feelings)
  4. Link belief in the facts to feeling for the other. (executive function)
  5. Value action for the wellbeing of the other. (feeling)
  6. Notice the needs of the other. (perception)
  7. Know how to meet the needs of the other. (skilled action)
  8. Prioritize action for the other over other priorities. (identity)
  9. Make action happen. (perseverance)

This pathway to action starts with cognition (reason, facts), integrates feeling, perception, motivation and action capacities. Any important action mixes facts and values but also more than that, such as slowing down the spread of a pandemic. 


Berry, W. (2013). It all turns on affection. 2012 Jefferson Lecture. Washington, D.C.: National Endowment for the Humanities.

Callicott, J. B. (2013). Thinking like a planet: The land ethic and the earth ethic. London: Oxford University Press.

Hume, D. (1888). A treatise of human nature. Oxford: Clarendon Press.

Leopold, A. (1991). The conservation ethic. In S.L. Flader & J. B. Callicott (Eds.), The river of the mother of God and other essays by Aldo Leopold (pp. 181-192). Madison: University of Wisconsin Press.

MacIntyre, A. (1969). Hume on ‘Is’ and ‘Ought.’ In W.D. Hudson (Ed.), The Is-Ought Question (pp. 35-50). London: Macmillan.

Moore, G.E. (1903). Principia ethica. Cambridge: Cambridge University Press.

Noddings, N. (2010). The maternal factor: Two paths to morality. Berkeley: University of California Press.