Philosophers have developed thought experiments to test philosophical theories and problems.
Ethics- judging right from wrong
Probably the main area of philosophy in which thought experiments are popular is ethics- the question of ‘right or wrong’ behaviour.
The two main contending perspectives in ethics are known as consequentialism (sometimes referred to as utilitarianism) and deontology or duty ethics.
Consequentialism judges right or wrong actions by reference to the consequences of an action- a cost-benefit type of approach in which results are regarded as more important than intentions. Results are judged to be right or wrong depending on how much pleasure or pain results for all people affected by the action.
Duty ethics judges right or wrong based on the extent to which an action conforms to universal principles of good conduct. Traditionally these principles were based upon religion, with God setting down a fairly rigid set or rules. Later Emmanuel Kant proposed that universal principles could be established by the application of reason.
Kant’s test for the formation of universal principles was “Act as you would want all other people to act towards all other people.” Act according to the maxim that you would wish all other rational people to follow, as if it were a universal law. This is similar but not identical to religion’s golden rule of “do unto others as you would have them do unto you”. Kant sees his maxim as being based on universal right behaviour which, unlike the golden rule, is not based on personal or subjective preferences as to how a person wants to treat or be treated in relation to others.
Kant also believed that we should never act in such a way that we treat humanity, whether in ourselves or others, only as a means to an end. We should treat ourselves or others as an end in itself. This is often seen the idea of “respect” for persons in that which is essential to our humanity.
The most famous thought experiment to test the different approaches of consequentialism as against duty ethics is the runaway trolley problem and variations on that theme.
The Trolley Problem: In this experiment a runaway trolley is charging towards five people on the trolley track, and you have the option of doing nothing or flicking a switch to divert the trolley onto a different track, where only one person is standing. If you do nothing you let five people die and if you flick the switch to divert the trolley this will cause the death of only one person. For most people this is a simple utilitarian equation- five deaths is worse than one so its best to flick the switch. The experiment also raises the issue about whether failure to do something within your power (flicking the switch) is an action.
The Fat Man: Similar to the trolley problem, in this experiment, there is the same runaway trolley, but this time, the only way to stop it is to push a fat man onto the tracks. This will stop the trolley but the fat man will die in the process. Again the dilemma is whether to sacrifice one life to save five others. Mathematically the result is the same as for the trolley problem- five deaths are worse than one. But people are far more hesitant to say they will push the man in front of the trolley than they are to say they will flick the switch. Somehow the direct physical contact involved in pushing the fat man to his seems more morally culpable to flick a switch through the results are the same.
The surgeon: In this experiment the surgeon experiment has five patients that are in need of organ transplants (heart, lungs, liver, kidneys, and pancreas). If they do not have the transplants they will soon die. A healthy man who has all of these organs and could save all five patients if they were harvested. But then the healthy man would die. The question is whether the surgeon should harvest the organs from the healthy person, knowing that it would result in his death, in order to save the lives of the five patients. Although the results are the same- sacrifice one life to save five- most people instinctively say that it would obviously be wrong to kill the healthy man to save the five. But would the answer change if the healthy man was Adolph Hitler and one of the people needing the harvested organ was Einstein? The result is more likely to change for the consequentialist than it is for the deontologist.
The controllable infectious disease: In this experiment a person contracts a highly infectious disease that is potentially disabling or fatal. It can be passed on by close contact, even by kissing. But the infected person is given a medicine which controls their symptoms and means they cannot pass the disease on to anybody else. But this is only guaranteed provided they take their medicine every day. If they fail to do this and miss a day, they might become infectious again. Another person wants to kiss them. The infected person knows that they never miss taking their medicine. But of course the person who wants to kiss them can’t know that for sure. Must the infected person tell the person who wants to kiss them tell them that they have the disease? Because the infected person has in fact taken the medicine and both parties will receive pleasure from kissing the consequentialist might conclude there is no compulsion to reveal the disease. The duty ethicist may be more likely to emphasise the right of the undisposed person to exercise full agency over their own health decisions .
Is maximising pleasure the only important thing?
The Experience Machine: Another thought experiment that strikes at the foundations of consequentialism- maximising pleasure- is the experience machine. This experiment raises the issue of whether pleasure is as important at authenticity or a whole life experience of which pain is a necessary part. This thought experiment imagines that there is a machine which you can plug into as to receive constant perfect/happy/pleasurable life experiences. Would you choose to live a life plugged into such a machine? The dilemma is whether to prioritise actual authentic, experience (which is certain to include pain) or constant pleasurable machine induced experience. The experiment also suggests that happiness is not only related to the prevalence of pleasant experiences in a person’s life but also has an ethical dimension.
Justice
John Rawls was philosopher who proposed a thought experiment called the “Veil of Ignorance” to explore the concept of justice.
In Rawls’ thought experiment, he asks us to imagine a group of people who are about to create a set of rules and institutions to govern their society. However, before they do so, they must first put on a “veil of ignorance” which prevents them from knowing what their own place in society will be, what talents and abilities they will have, and whether they will be rich or poor. They must then make decisions about what the rules should look like, without knowing how those decisions will affect them personally.
The purpose of the veil of ignorance is to eliminate bias and self-interest from the decision-making process. Rawls argues that if people do not know what their place in society might be, they will be more likely to create rules that are fair and just for everyone, regardless of their individual circumstances.
Rawls believes that if people were to make decisions behind the veil of ignorance, they would come up with two fundamental principles of justice- that each person should have an equal right to basic liberties such as freedom of speech and religion and that inequalities in society should only be allowed if they benefit everyone, particularly the least advantaged members of society.
Rawls’ thought experiment has been influential in the fields of philosophy, political science, and economics, and has inspired much discussion and debate about what a just society should look like.
What is change?
The Ship of Theseus experiment asks the question what is change?: This thought experiment involves a ship that is gradually replaced piece by piece until none of the original parts remain. The question is whether the ship is still the same ship, or if it has become a different ship entirely. The biologist Richard Dawkins tells us we don’t have a single atom in our body as adults as we had as children. We are more like waves in an ocean that rocks. So to what extent are we really the same person in old age as when we are young?
It is impossible to be all powerful.
The Omnipotence Paradox: This thought experiment challenges the existence of an all powerful God by asking whether such a God can create a stone that is to heavy for him/her to lift. The paradox raises questions about the limits of omnipotence and the nature of logical contradictions. If the so-called all powerful Go cannot create a rock to lift the God is not all powerful because it can’t create such a rock. But if the God can create such a rock it is not all powerful because it cannot lift it.