Utilitarianism

**Utilitarianism** is one of the most influential theories in ethics, and one of the main viewpoints relevant to the Trolley Problem. It lies in contrast with Deontology.

## Concept

Utilitarianism is a type of Consequentialism, which argues that the moral nature of decisions depend on their consequences, rather than the natures of the actions themselves. Utilitarianism, specifically, quantifies the concept of "happiness" and "pleasure" in the form of "utility", and argues that the correctness of moral decisions depends on their effect on the net utility among all stakeholders. Pain and sufferings are thought to be the opposite of happiness and pleasures, and therefore translate into negative amounts of utility.

Utilitarians seek to maximize the total amounts of utility and prefer to make decisions that either increase the total amount of happiness or reduce the total amount of sufferings. Utilitarians believe that the ends always justifies the means, and unlike deontologists, are willing to go against traditional moral guidelines in order to achieve their goals.

The utility of a life is assumed by some utilitarians to simply be the sum of all utilities experienced by an individual throughout their lifetime, although this is debatable, as other utilitarians may assume that the choices and identities of an individual yield additional utility.

### Assumptions about the Calculation of Utility

Utilitarians often assume that most arithmetic properties - that apply to numerical quantities - would also apply to utility. For example, given an experience A:

* An experience which lasts five times as long as A, but is otherwise identical to A, is often assumed to yield five times as much utility as A.
* Five different people experiencing A is often assumed to yield five times as much utility as one person experiencing A.
* A, experienced five different times by a single person, is often assumed to yield five times as much utility as A experienced once.

In addition:

* Five lives are often assumed to yield five times as much utility as one life.
* Five years of life is usually assumed to yield five times as much utility as one year of life.

These assumptions are sometimes debatable, depending on the exact context.

### Probabilistic Assumptions

When an utilitarian moral agent does not know the certain outcome to each decision, but is instead aware of the probability of each outcome, it is often assumed that the moral agent can use these probabilities to evaluate an expected utility value, the comparison of which will determine the preferred decision. For example, consider a situation where decision A will save 1 life for sure, while decision B will save 5 lives with a probability of 50%, and not save any life otherwise. The utilitarian may consider their options in the following manner:

1
×
# 1
1

{\displaystyle 1 \times 1 =1}
 Decision B

5
×
# 0.5
2.5

{\displaystyle 5\times0.5=2.5}

Since Decision B yields a greater expected utility, Decision B may be considered the preferred option. However, the assumption that moral decisions can be evaluated through probabilistic expectations is debatable and may not be universally accepted by all utilitarians. There may exist, for instance, alternate assumptions, or variants, that considers decisions with certainties of outcomes (such as, in this case, decision A) to be preferable to decisions with uncertainties of outcomes (such as, in this case, decision B).

A challenge that the probabilistic assumptions of utilitarianism may face is the existence of situations in which probabilities cannot, or cannot easily become known to the moral agent - for example, a situation where the outcome of a decision depends on the decision of another moral agent, which may be difficult or impossible to estimate.

## Relations to Other Concepts

The idea of "utility" requires an underlying value theory to specify what is considered utility and how they are quantified and compared. The choice of such a value theory will influence the species of utilitarianism.

Like other Consequentialist theories, Utilitarianism requires an underlying theory of Causality to specify what is considered the consequence of a decision. The choice of a theory of causality will influence the species of utilitarianism.

While the concept of Utilitarianism does not explicitly specify whether the utility of an experience (viewed as an internal object) is subjective or objective, it is usually assumed that utility is objective. A possible exception is the sub-theory of Preference Utilitarianism, which, depending on how it is stated, either regards utility itself to be subjective with respect to personal preference, or requires preference to be considered the fundamental element of utility.

Since utility is usually assumed to be objective, most forms of Utilitarianism are consistent with a Realist meta-ethical premise.

## Sub-Theories and Variations

### Mill's Utilitarianism

John Stuart Mill (1806~1873), one of the most important utilitarian philosophers, proposed a distinction between higher and lower pleasures (or enjoyments). According to Mill, some classes of enjoyment (and correspondingly, of utility) are absolutely superior to others, so much so that no quantity of the latter would suffice to make up for even a small amount of the former. An example that he raised was the superiority of intellectual enjoyments over that of sensual enjoyments. Mill's Utilitarianism is an important counterargument to the idea that "pigs are happier than philosophers", which threatens the validity of Utilitarianism as a whole, as being a philosopher is intuitively more desirable than being a pig. According to Mill's Utilitarianism, the premise of pigs being happier than philosophers is false, since pigs, despite being more carefree than philosophers, have little chance to experience intellectual enjoyments, which are deemed absolutely superior to all kinds of enjoyments pigs have access to.

Utility, like most physical quantities, is usually regarded as a real number. However, Mill's Utilitarianism implies the existence of some positive utility that is infinitely greater than another positive utility, which can never be demonstrated by any pair of real numbers. Let us consider an utility A to be of a different class from an utility B if neither is a real product of the other. Assuming that all possible classes of utility can be contained in a set, the set of all utilities forms a vector space (which is the set of real numbers only if there is only one class of utility - something that Mill rejected).

While Mill had suggested the existence of classes of utility that are absolutely superior to others, he had not explicitly suggested that the set of all such classes is well-ordered according to the absolute superiority that he proposed. However, such a well-ordering may be necessary for there to exist a total ordering of all utility in a way that is consistent with Mill's theory. Since Utilitarianism as a whole is largely concerned with the comparison (or ordering) of utility, the non-existence of a total ordering will pose a serious theoretical problem.

Under Mill's Utilitarianism, some bold assumptions about the algebraic nature of utility will no longer hold true. There may be other sub-theories or variations of Utilitarianism that, for different reasons, require us to consider utility as something other than real numbers - such as vectors, or concepts further more difficult to work with.

John Stuart Mill had many contributions towards utilitarian theory other than the distinction of higher and lower pleasures. Therefore, “Mill’s Utilitarianism” would also include more concepts than that alone. Nevertheless, it is still correct, in the context of this article, to refer to any such view as Mill’s Utilitarianism.

### Act Utilitarianism vs. Rule Utilitarianism

Act Utilitarianism and Rule Utilitarianism are contrasting sub-theories concerned with whether a moral decision should be considered individually or universally, and whether a moral decision should be concerned with its influence on other moral agents and on future decisions.

Those who follow **Act Utilitarianism** are concerned only about the consequences of their decisions in the context of a single instance.

Those who follow **Rule Utilitarianism** are concerned about the effect of their actions when applied universally. Rule Utilitarianism is sub-divided into **Strong Rule Utilitarianism**, where actions are always evaluated according to whether an universal application of the principles across all moral situations and all moral agents would result in an overall increase or decrease in utility, and **Weak Rule Utilitarianism**, which emphasizes the effect of on a moral decision on social expectations and consensus.

The two sub-classes of Rule Utilitarianism differ in that Strong Rule Utilitarianism shares similar traits with deontological ethical theories since it revolves on the theoretical effects of an action, while Weak Rule Utilitarianism, in a similar spirit as Act Utilitarianism, focuses on the practical effects of an action. For example, an act utilitarian representing a certain community is more willing to lie in his official or professional capacity if doing so can prevent a disaster, even if doing so diminishes an important sense of trust that the public has in this community. A weak rule utilitarian in the same situation would be less willing to lie, but this sense of truthfulness is not out of obedience to certain moral rules, but instead, in consideration of the negative effects of the erosion of trust that will result from lying.

A demonstration to the value of Weak Rule Utilitarianism is the Organ Transplant thought experiment. While weak rule utilitarians would usually agree with pulling the lever in the original trolley problem, they would be opposed to sacrificing the healthy patient - despite the seemingly similar nature of these two actions. This is because killing the patient severely undermines public trust in the healthcare system, and result in more people refusing to seek medical treatments despite its availability.

Weak Rule Utilitarianism can be considered a basis for the principles of justice and criminal deterrence. While, under Act Utilitarianism, rehabilitation would be considered the optimal treatment to criminals, Weak Rule Utilitarianism provides a supporting argument for favoring harsh penalties, such as long sentences, capital punishments, and corporal punishments, over rehabilitation. The argument is that harsh penalties will discourage people from (unnecessarily) committing crimes, hence improving quality of life in the society and also reducing the number of people who will face criminal penalties.

Weak Rule Utilitarianism can be considered the basis of many other aspects of the social contract that do not follow the logic of Act Utilitarianism. Due to the existence of Weak Rule Utilitarianism, Utilitarianism as a whole is in fact more compatible with the intuitive ideas in morality that it seems.

### Total Utilitarianism vs. Average Utilitarianism

Total Utilitarianism and Average Utilitarianism are contrasting sub-theories concerned with whether the size of a population affects the utility that it yields, given the same quality of life.

**Total Utilitarianism** consider the utility of a population to be the sum of all utilities of individual members. Therefore, when members have positive utility, total utilitarianism favors a larger population size given the same average utility.

Total Utilitarianism is oftentimes a supporting argument for increasing birth rate - especially in developed countries where shortage of resources is not a problem (meaning that an additional member to the society will enjoy high quality of life while doing relatively little damage to it). However, this argument comes with a highly debatable assumption - that the average utility experienced by members of the current society (or even any society at any level of technology) in the course of their life is a positive.

Total Utilitarianism suffers the problem that a comparison of utility between two populations would require us to multiply average utility by population size. While utility is regarded by utilitarians as a quantity, it is almost never possible to justifiably give a ratio between the utility yielded by two different kinds of experiences (although a simple ordering may be possible). For example, while most utilitarians agree that the life of a cow is worth less utility than that of a human, there is no consensus to how many cows would be utility-equivalent to one human (alternatively, it is also possible to argue, as per Mill's Utilitarianism, that the life of one human is infinitely more valuable than that of a cow).

However, it is worth noting that comparing the ratio of utility is an unresolved problem relevant to utilitarianism as a whole, and as such, it does not necessarily discount the notion of Total Utilitarianism.

**Average Utilitarianism** considers the utility of a population to be the average of all utilities of individual members.

Compared to Total Utilitarianism, Average Utilitarianism is more intuitively compatible with the notion that it is better for a country to become a first-world country with a small population than to become a third-world country with a large population. However, on closer examination, Total Utilitarianism may be at least just as compatible if we regard the average utility of a third-world country as a negative (and if it is a positive, it may be only a little above zero, and therefore only a small fraction compared to the average utility of a first-world country).

The most obvious issue with Average Utilitarianism is that it seems to suggest that it is justifiable to kill off a large fraction of the population to leave behind only the happiest ones, which goes against moral intuition. However, it can also be argued that a massive reduction of population size will severely impede technological and social progress, undermining future quality of life, and therefore would not be supported by either sub-theory.

Another issue that Average Utilitarianism faces is that the high average utility of a population may be diluted if it is considered in combination with a large population with very low (or negative) average utility, resulting in contradictory conclusions. A population with somewhat lower average utility but higher total utility, when combined with the said large population, will be more resistant to such a dilution. Below is an example to illustrate: We have a population A with a high average utility of 10 units but a small population size of 1 unit, and a population B with a medium average utility of 5 units and a relatively larger population size of 5 units. Let us consider another population, S, with a low average utility of 1 unit and a large population size of 10 units. Notice that the combination of A and S, which we denote A+S, is a population of size 11 and total utility 20, giving us an average utility of about 1.82. The combination of B and S, which we denote B+S, is a population of size 15 and total utility 35, giving us an average utility of about 2.33. This means that B+S has higher average utility than A+S. If Average Utilitarianism is true, this means that S, being a population separate from both A and B, has a direct influence over which of the two population is superior utility-wise, which would seem logically absurd. Therefore, in order to be a consistent theory, Average Utilitarianism may require a concurrent consideration of how equally utility is distributed.

### Negative Utilitarianism

**Strong Negative Utilitarianism** is a variation where only undesirable, negative-value, forms of utility (e.g. sufferings) are considered when making an evaluation. **Weak Negative Utilitarianism** considers both positive and negative forms of utility, but gives lower weights to positive utility. One important motivation for Negative Utilitarianism is the seemingly problematic conclusion from classical utilitarianism that a decision that puts many people in great sufferings would be morally good if the amount of happiness it provides other people (or perhaps the same people but at different times) still over-weighs the sufferings. Such a conclusion would come directly at odds with the popular and somewhat intuitive notion of human rights. Negative Utilitarianism, on the other hand, is less permissive (or in the case of Strong Negative Utilitarianism, not permissive) of putting people through sufferings in order to achieve net happiness.

A major problem that Negative Utilitarianism faces is the idea of a “benevolent world exploder”, where a painless erasure of all life in the world appears, according to Strong Negative Utilitarianism, to be a morally good decision. Weak Negative Utilitarianism suffers less of the same problem, as even though the total utility experienced by a typical individual during their lifetime is evaluated by negative by some Weak Negative Utilitarians (and by some classical utilitarians), many people expect the positive utility of living to increase due to technological and social progress so as to eventually overwhelm negative utility despite the difference in weight. Weak Negative Utilitarianism also suffers its own problem, as it is difficult to justify the idea that positive utility is still considered, but for some reason, simply given some lower weight. The choice of weight is also difficult to justify.

A variation of Weak Negative Utilitarianism combined with Mill’s Utilitarianism may be able to resolve the “benevolent world exploder” thought experiment while still remaining well-justified: we may, as per Mill’s Utilitarianism, consider only the more superior classes of enjoyments to be as worthy of consideration as negative forms of utility.

## Relations to Other Normative Ethics Theories

### Egalitarianism

It should be noted that pure utilitarianism does not treat "equity" or "fairness" as inherently good outcomes, and therefore does not take them into direct account. Egalitarian concepts still influence the utilitarian evaluation of moral decisions, but only indirectly through their effects on net utility.

The Utility Monster thought experiment involves a special individual called the "utility monster", who, by consuming one unit of resources, experiences many times the utility experienced by a normal individual consuming the same amount of resources. As utilitarianism favors the maximization of utility, an utilitarian allocation of resources would result in disproportionate amounts of resources being consumed by the utility monster. This is unequal both in terms of resource allocation and in terms of utility gain, therefore violating egalitarian ideals. This thought experiment illustrates that Utilitarianism and Egalitarianism may not be compatible.

Utilitarianism, at other times, lends support to Egalitarianism. Since pure Utilitarianism is concerned about only the sum of utility and not how equally they are distributed, it may at first seem that utilitarians are indifferent towards wealth inequality. However, wealth cannot be translated to utility as the relationship between the two is not linear. Someone who owns 1 billion would have a far higher quality of life than a beggar, while someone who owns 2 billion would not be much happier than someone who owns 1 billion. As utility, as a function of wealth, is downward-concaving, a more equal distribution of wealth (for example, a billionaire giving half of his money to a beggar) will most likely lead to a net utility increase, and therefore be favored by most utilitarians. (Of course, the actual situation is more complex, since some consider the difficulties individuals face in gathering wealth to be a driving factor for self-improvement and social development.)

The above explanation demonstrates how utilitarianism can be used as an alternate way to arrive at egalitarian conclusions. Therefore, an utility-centric view may regard egalitarian concepts as the products of utilitarianism rather than something inherent.

## Implications, Criticisms and Defense

### Problem of Past and Future

Consider a thought experiment where we are given an opportunity to change someone's painful experience in the past to a happy experience. There is the additional condition that while the past experience itself will change, it will not alter other events in the timeline, and the person's memory will be left as it is. Intuitively, it does not matter whether we change the experience, as the experience had already transpired, cannot be experienced again, and will not affect any present or future events. However, if we are given the same opportunity but before the experience occurs, it would seem, according to conventional utilitarianism, that we should change the experience. As the two opportunities present the exact same outcome, they should be morally equivalent from a Consequentialist viewpoint, but our intuition in the first case favors a different judgement from what conventional utilitarianism tells us in the second case. If we agree with our intuition, we appear to reach the conclusion that any single experience that will eventually end, and by extension, any action whose direct and indirect consequences will eventually vanish, is not morally relevant. This, still assuming utilitarianism is true, means that only experiences lasting forever, and actions whose influence last forever, will be morally significant. The existence of such experiences or actions requires the universe itself to last forever, something modern science has yet to agree on, while the nonexistence will render utilitarianism equivalent to a nihilist theory.

A similar issue is that most people would prefer experiencing something tormenting followed by something enjoyable rather than going the other way round, while most forms of utilitarianism do not take the order of events into account.

### Inequality

As the Utility Monster thought experiment demonstrates, the most utilitarian choice does not necessarily match the most egalitarian one, and the two may even be polar opposites of each other. Another example is that a purely utilitarian society would be willing to doom a small group of people to grave sufferings in order to achieve a relatively small increase quality of living for the rest. In such cases, utilitarianism seems to contradict our visions of an ideal society.

### Unpredictability of Other Moral Agents

A single consequence may have multiple causes or steps leading to it, each of which may be attributed to a different decision or set of decisions. In an universe where some form of free will exists, there may be no such thing as “the probability that a certain moral agent will make a certain decision”, since decision-making via free will may be free from probabilistic factors.

Therefore consider the following thought experiment: if a head surgeon starts a surgery on a patient, they cannot know the probability (and there may not exist any value for probability, not even an undiscoverable one) that their assistant will for whatever reasons decide to abort their duties as a medical professional and leave the surgery room. If the assistant makes such a decision, the patient will die, and the decision of the head surgeon to start the surgery will be partly responsible for this outcome, because if the surgery was never started in the first place, there is no way for it to be left unfinished and cause the patient to die. In an universe where free will does not exist, the expected utility of the decision can still be evaluated probabilistically, but in an universe where free will is free from probabilistic restraints, and where values for the probability of decisions is undecidable or nonexistent, the expected utility of decisions also does not exist. This poses a serious theoretical problem to utilitarianism.

### Butterfly Effect and Divergence of Utility Sum

To calculate the expected utility of a decision, we must technically account for all consequences of the decision, no matter how indirect or far in the future they are. However, due to butterfly effect, the possible indirect consequences of a decision, even when weighed by a small value for probability, may far outweigh the direct consequences, making it extremely difficult to calculate the expected net utility change. As consequences can extend infinitely into the future, an account for all the consequences would require us to take an infinite sum, which will most likely diverge, rendering the expected consequences indeterminate.