Foundations of bioethics: is, ought and values
- Theory
Facts alone do not tell us what we ought to do: a clinical decision joins data, values and duties.
What it is
A basic question in bioethics is how we move from facts (what is) to norms (what ought to be). David Hume (A Treatise of Human Nature, book 3) noted that many authors slip without explanation from statements with «is» to conclusions with «ought»; the most widespread reading is that no moral conclusion follows validly from factual premises alone. G. E. Moore (Principia Ethica, 1903) called defining the good by a natural property, such as pleasure, the «naturalistic fallacy», and offered the open question argument: even if something is pleasant, it still makes sense to ask whether it is good. For the clinic, the lesson is practical: data (prognosis, risks, evidence) are necessary but not enough; the values at stake (life, quality of life, autonomy, justice) and the duties that follow from them must be made explicit. That is why case-analysis methods separate facts, values and duties.
Core ideas
- Facts: diagnosis, prognosis, options, risks, context; established with the best evidence.
- Values: what matters to the people involved (life, health, autonomy, beliefs, justice).
- Duties: what ought to be done, which arises from joining facts and values with reasons.
- A duty is never justified by a fact alone: «life can be prolonged» does not imply «life must be prolonged».
- Human dignity: the base value that UNESCO and the 1991 Constitution set as a foundation.
In clinical practice
- «The treatment extends life by three months» is a fact; whether it should be offered also depends on the patient's values and the burden of treatment.
- «Technically possible» does not equal «right»: limiting life-sustaining treatment starts from that distinction.
- In committee discussions, separating «what we know», «what we value» and «what we ought to do» reduces misunderstandings.
- A clinical practice guideline summarises evidence; applying it to a particular patient takes a value judgement.
Criticisms and limits
- Some authors read Hume differently: facts about the effects of a trait can support moral conclusions if one starts from moral sentiments.
- Several philosophers argue that some concepts are both descriptive and evaluative (such as «cruel»), which blurs the line between fact and value.
- Separating facts and values does not mean values are arbitrary: they can be reasoned about and discussed.
- Political Constitution, art. 1: the State is founded on respect for human dignity; official text checked on 2026-11-13 in the Función Pública Gestor Normativo.
Test yourself
Think of the answer, then tap the question to see it.
What problem did Hume point out about «is» and «ought»?
That many authors slip without explanation from statements about what is to conclusions about what ought to be; the common reading is that the second does not follow from the first alone.
What is the naturalistic fallacy according to Moore?
Defining the good by a natural property, such as pleasure; Moore attacked it with the open question argument.
Why is clinical evidence not enough to decide what to do?
Because data say what is possible and with what result, but deciding what ought to be done also needs the patient's values and the doctor's duties.
Which three levels do case-analysis methods separate?
Facts, values and duties.
Connections
Educational content on ethics and health law; not legal advice. Laws and case law change: each page links the official text and says when it was last checked. For a real case, read the text in force and ask a lawyer or the medical ethics tribunal.
Sources: Hume's Moral Philosophy (Stanford Encyclopedia of Philosophy, 2018); Moral Non-Naturalism (Stanford Encyclopedia of Philosophy, 2025); Universal Declaration on Bioethics and Human Rights (UNESCO, 2005); Constitución Política de Colombia 1991 (Función Pública, Gestor Normativo, 1991).
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Representative model, for educational purposes only.