Medical Ethics: the Four Pillars, Deontology and Consequentialism Explained

A closer look at key ethical principles and theories that you should be aware of as a medical school applicant, medical student or doctor.

March 2021
Sana Khan (Blogger)
Aston University - 1st Year Medical Student

What is medical ethics?

BMA definition: ‘The application of ethical reasoning to medical decision making’ (BMA 2020).

There will be many times in your career as a doctor that you will have to make a difficult decision, where there is no clear right or wrong answer, and justify it. Medical ethics are the basis of what will guide your decision making as a doctor so you need to have a good idea of them and be able to show your interviewer that you have the capability to make such decisions in the future. Of course, you will receive training for this during medical school, but the objective of the interview is to see whether you can weigh up the different outcomes, apply ethical principles and reach a final decision.

Therefore it’s important that you familiarise yourself with the following concepts. Make sure you are able to use these keywords when forming your arguments and justifying your decisions so that you are prepared if you are asked to discuss an ethical scenario in a medical school interview.

The ethical principles that form the foundation of decision-making in medicine are referred to as the ‘Four Pillars of Medical Ethics’.

But,

What are the ‘Four Pillars of Medical Ethics’?

1. Autonomy

This is the most important pillar of medical ethics. It gives patients who are competent enough the right to make decisions about their own healthcare. Essentially, it means that the patient has a say and is in charge of their own care.

An example of autonomy: If a doctor needs to take a patient’s bloods then the consent of the patient is important. The patient has the right to refuse the blood test.

Note: in the aforementioned scenario we are assuming that the patient has the capacity to consent (we won’t go into too much depth about what capacity to consent entails in this specific blog post!).

2. Non-maleficence

This principle states that a medical professional will not do harm to a patient intentionally or show neglect. It is also worth considering whether short term harm outweighs long term benefit.

An example of non-maleficence: a surgeon will not operate on a patient in a non sterile environment because that will cause harm to the patient.

3. Beneficence

This principle means that medical practitioners will always act for the benefit of their patients. However, there is a risk of this becoming paternalistic. It also poses some conflicts in some scenarios: for example, when a Jehova’s Witness needs a blood transfusion.

An example of beneficence: if a patient requests antibiotics but the doctor knows of a better alternative treatment, then the doctor will use their expertise to give the patient the treatment that is best for them.

4. Justice

This considers whether an action is ethical, compatible with the law, respects the patient’s rights, and is fair and balanced.

An example of justice: fair distribution of resources in a hospital.

It is also worth considering different ethical theories.

But first,

What is the difference between ethical theories and principles?

Ethical theories guide you in the process of decision making whereas ethical principles are the common goals that each theory tries to achieve in order to be successful. Two ethical theories I am going to discuss are deontology and consequentialism.

What is deontology?

This is an ethical approach whereby it is the intention behind a particular action rather than the consequence of that action which will make the action a ‘good’ or ‘bad one. According to deontology, there are three categorical imperatives which we have a duty to follow. These are as follows:

1. Act only on maxims which you can will to be the universal laws of nature.

So how would it be if everyone did that action? If you are to commit a theft, what will the consequences be if everyone committed theft? We would live in a dishonest society with a lot of crime which would be very unpleasant. Therefore you shouldn’t commit that theft.

2. Always treat the humanity in a person as an end and never as a means to an end.

In the medical setting this can be applied to appointments: we shouldn’t rush appointments just to get to the next patient, we must give the patient at hand all our attention and treat them as best as we can.

3. Act as if you were a member of an ideal kingdom of ends, in which you were both subject and sovereign at the same time.

This means to act as part of the community and respect each other.

What is consequentialism?

This is an ethical approach whereby an action is right or wrong based upon its consequences, rather than the intention behind it. However, the problem with this is that anything can be justified on the basis of the ‘good’ of the many.

Can you think of any examples of acts that may seem ‘bad’ but justified on the basis of its consequences?

It may help to consider utilitarianism which states that the morally correct decision is the one that maximises wellbeing for the greatest number of people.

The Trolley Problem

With this in mind, let’s take a deep dive into the trolley problem. Please have a think about what you would do in this scenario before looking at any youtube comments or reading my answer.

Watch this video: https://youtu.be/bOpf6KcWYyw

The first thing to establish is that whatever you do, whether you choose to do nothing, change the lever or push the man off the bridge, will cost lives. So the aim is to think about the lesser evil and thus what the best and morally right thing will be to do in this scenario.

Consider the consequences of changing the lever. When I first thought about it I was thinking about the ‘lesser of the two evils’. You effectively save five lives if you pull the lever and if you don’t then only one life is saved. And since all six of those people are workers, more likely than not they all have people and family members who are dependent on them. So, saving five of those will mean five families are being saved. But what about the other family? The one who’s breadwinner has died. Were they less important or was that man’s life less important just because there was one of him and five of the others? Is that fair? No, it’s not fair, but we’re trying to achieve the best outcome for the biggest number of people (utilitarianism). Unfortunately, such decisions have to be made.

But my real argument is this: why were those five people standing in such a dangerous place? Weren’t they aware that a train could come? Whereas the man who is on the other end of the track was playing safe on his part and was perhaps standing there for his own safety, knowing that no trains would come his way. If he’s made a sensible decision and the other five haven’t, is it ethically right to override their choices and cause the man who cared about his safety to die? Moreover, if you pull the lever you are actively causing the man who is on the safe side of the track to die. Therefore, if put in this situation I personally wouldn’t pull the lever because to me it seems immoral to put someone in danger who seems to be keeping themselves safe, just because it would save the lives of five individuals.

What would you do? Justify your answer.

And will your decision remain the same or change if we were considering pushing the fat man over the bridge? Why is that?

Now let's apply this to a medical scenario and think of it in terms of transplantations.

Interview question:

There is one liver available for transplantation. Who would you give the liver to?


  1. A 33 year old alcoholic man who has damaged his liver due to alcohol abuse.
  2. A 68 year old man who is fit and healthy but has damaged his liver due to old age.

Remember to justify your decision and more importantly, make a decision! This is a typical interview question. They will give you a set of patients and ask you to rank them in order of deservingness. Remember to think out loud and explain your reasoning but also give the ranking at the end as well. Some students just talk through and discuss the options but don’t give a final answer. This will cost you marks so make sure you make a clear decision!

Author: Sana Khan

Editor: Allegra Wisking

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