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Education Standards

2.2 Critical Evaluation of Moral Theories

2.2 Critical Evaluation of Moral Theories


Excerpt edited for the General Intro to Ethics Student:
Ethics for A-Level: Introduction -Mark Dimmock and Andrew Fisher, Ethics for A-Level. Cambridge, UK: Open Book Publishers, 2017, (CC BY 4.0). 

[Image - olarte.ollie, "detective" - licensed by CC BY-SA 2.0]

Evaluating Ethical Theories

"Philosophy, Ethics and Thinking

"Philosophy is hard. Part of the reason it can feel so annoying is because it seems like it should not be hard. After all, philosophy just involves thinking, and we all think — thinking is easy! We do it without…well, thinking. Yet philosophy involves not just thinking, but thinking well. Of course it is true that we all think. But thinking, like football, maths, baking and singing is something we can get better at. Unfortunately, people rarely ask how...

...if you engage with philosophy, then you will be developing yourself as a thinker who thinks well... perhaps heading off to make decisions in law, medicine, structural engineering — just about anything that requires you to think effectively and clearly.

However, if Philosophy is hard, then Ethics is really hard. This might seem unlikely at first glance...

Respecting Ethics

When you study… Ethics, and you evaluate what is right and wrong, it can be tempting and comforting to spend time simply defending your initial views; few people would come to a debate about vegetarianism, or abortion, without some pre-existing belief. If you are open-minded in your ethical approach then you need not reject everything you currently believe, but you should see these beliefs as starting points, or base camps, from which your enquiry commences.

For example, why do you think that eating animals is OK, or that abortion is wrong? If you think that giving to charity is good, what does “good” mean? For true success, ethics requires intellectual respect. If you might think that a particular position is obviously false, perhaps take this reaction as a red flag, as it may suggest that you have missed some important step of an argument — ask yourself why someone, presumably just as intellectually proficient as yourself, might have once accepted that position.

If you are thinking well as an ethicist, then you are likely to have good reasons for your views, and be prepared to rethink those views where you cannot find such good reasons. In virtue of this, you are providing justification for the beliefs you have. It is the philosopher’s job, whatever beliefs you have, to ask why you hold those beliefs. What reasons might you have for those beliefs?

For example, imagine the reason that you believe it is OK to eat meat is that it tastes nice. As philosophers we can say that this is not a particularly good reason. Presumably it might taste nice to eat your pet cat, or your neighbour, or your dead aunt; but in these cases the “taste justification” seems totally unimportant!... The point is that there are good and bad reasons for our beliefs and it is the philosopher’s job to reveal and analyse them."

-Ethics for A-Level: Introduction -Mark Dimmock and Andrew Fisher, Ethics for A-Level. Cambridge, UK: Open Book Publishers, 2017,

5 Keys to Doing Ethics Well

5 Keys to Doing Ethics Well

  1. Legality vs. Morality
  2. Prudential Reasons vs. Moral Reasons
  3. Prescriptive vs. Descriptive Claims
  4. Thought-Experiments
  5. Understanding Disagreement

Doing Ethics Well: Legality versus Morality

"Moral questions are distinct from legal questions, although, of course, moral issues might have some implications for the law. That child labour is morally unacceptable might mean that we have a law against it. But it is unhelpful to answer whether something is morally right or wrong by looking to the laws of the land. It is quite easy to see why. Imagine a country which has a set of actions which are legally acceptable, but morally unacceptable or vice versa — the well-used example of Nazi Germany brings to mind this distinction. Therefore, in discussions about ethics do be wary of talking about legal issues. Much more often than not, such points will be irrelevant.

Doing Ethics Well: Prudential Reasons versus Moral Reasons

Something to keep separate are moral reasons and prudential reasons.

Prudential reasons relate to our personal reasons for doing things.

Consider some examples. When defending slavery, people used to cite the fact that it supported the economy as a reason to keep it. It is true, of course, that this is a reason; it is a prudential reason, particularly for those who benefited from slavery such as traders or plantation owners. Yet, such a reason does not help us with the moral question of slavery. We would say “OK, but so what if it helps the economy! Is it right or wrong?”

Doing Ethics Well: Prescriptive versus Descriptive Claims

Another important distinction is between descriptive and prescriptive claims. This is sometimes referred to as the “is/ought” gap...

Consider some examples. Imagine the headline: “Scientists discover a gene explaining why we want to punch people wearing red trousers”. The article includes lots of science showing the genes and the statistical proof. Yet, none of this will tells us whether acting violently towards people wearing red trousers is morally acceptable. The explanation of why people feel and act in certain ways leaves it open as to how people morally ought to act.

Consider a more serious example, relating to the ethics of eating meat. Supporters of meat-eating often point to our incisor teeth. This shows that it is natural for us to eat meat, a fact used as a reason for thinking that it is morally acceptable to do so. But this is a bad argument. Just because we have incisors does not tell us how we morally ought to behave. It might explain why we find it easy to eat meat, and it might even explain why we like eating meat. But this is not relevant to the moral question. Don’t you believe us? Imagine that dentists discover that our teeth are “designed” to eat other humans alive. What does this tell us about whether it is right or wrong to eat humans alive? Nothing.

Doing Ethics Well: Thought-Experiments

... the philosophical device known as a “thought experiment”. These are hypothetical, sometimes fanciful, examples that are designed to aid our thinking about an issue.

For example, imagine that you could travel back in time. You are pointing a gun at your grandfather when he was a child. Would it be possible for you to pull the trigger? Or, imagine that there is a train running down a track. You could stop it, thereby saving five people, by throwing a fat man under the tracks. Is this the morally right thing to do?

"The Good Place" Illustration of the Trolley Problem Thought Experiment

The details here are unimportant. What is important, is that it is inadequate to respond: “yes, but that could never happen!” Thought experiments are devices to help us to think about certain issues. Whether they are possible in real life does not stop us doing that thinking. Indeed, it is not just philosophy that uses thought experiments. When Einstein asked what would happen if he looked at his watch near a black hole, this was a thought experiment. In fact, most other subjects use thought experiments. It is just that philosophy uses them more frequently, and they are often a bit more bizarre.

Doing Ethics Well: Understanding Disagreement

Finally, we want to draw your attention to a common bad argument as we want you to be aware of the mistake it leads to. Imagine that a group of friends are arguing about which country has won the most Olympic gold medals. Max says China, Alastair says the US, Dinh says the UK. There is general ignorance and disagreement; but does this mean that there is not an answer to the question of “which country has won the most Olympic gold medals?” No! We cannot move from the fact that people disagree to the conclusion that there is no answer. Now consider a parallel argument that we hear far too often.

Imagine that you and your friends are discussing whether euthanasia is morally acceptable. Some say yes, the others say no. Each of you cite how different cultures have different views on euthanasia. Does this fact — that there is disagreement — mean that there is no answer to the question of whether euthanasia is morally acceptable? Again, the answer is no.

That answer did not follow in the Olympic case, and it does not follow in the moral one either. So just because different cultures have different moral views, this does not show, by itself, that there is no moral truth and no answer to the question..."

Ethics for A-Level: Introduction -Mark Dimmock and Andrew Fisher, Ethics for A-Level. Cambridge, UK: Open Book Publishers, 2017,


"…we hope that we have signposted some errors to avoid when it comes to thinking about ethics, and some strategies to consider instead. It may be worth occasionally revisiting the ideas discussed here during your studies, to test your own lines of argument and evaluate how “thinking well” is progressing for you. This would not be a weakness! Both the authors, and any honest philosopher, can reassure you — philosophy is hard!..."

Ethics for A-Level: Introduction -Mark Dimmock and Andrew Fisher, Ethics for A-Level. Cambridge, UK: Open Book Publishers, 2017,

Review Questions & Tasks

  1. What is the difference between prudential and moral reasons?
  2. What is meant by the “is/ought” gap? Why is it important to remember when discussing ethical questions?
  3. What role, if any, does science have in ethical arguments?
  4. What are thought experiments? Why might they be useful to philosophers?
  5. “Because there are so many different views on moral issues there cannot be any moral truth”. What do you think of this line of argument?

Ethics for A-Level: Introduction -Mark Dimmock and Andrew Fisher, Ethics for A-Level. Cambridge, UK: Open Book Publishers, 2017,