Is Morality Natural or Supernatural?

Metaphysicians appealing to the supernatural identify one or more of the following features of morality as essential:

1. Moral laws are normative.
2. Moral judgments purportedly report facts.
3. Moral laws are categorical.
4. Moral laws are universal.
5. Moral agents develop virtuous character.

I will now elaborate on each of these features while drawing out the analogy with our system of traffic laws.

1. 1.
   Moral laws are normative.

Moral laws are action guiding, providing reasons for acting according to certain constraints. Each moral code provides a set of behavioural norms for the people within the scope of that code. 'You ought not cheat on your taxes' gives tax-payers a reason not to take advantage of the tax system.

Similarly, traffic laws are action guiding. Each region's traffic code specifies a set of norms for driving in that region. Traffic norms clearly and unambiguously mirror moral norms. For example:

We do not appeal to a transcendental lawgiver or some mysterious metaphysical quality of the universe to justify obeying road rules. Whichever natural explanation we use to ground the normativity of road rules applies equally to the 'oughtness' of moral rules.

1. 2.
   Moral judgments purportedly report facts.

Moral judgments, such as 'Stealing is wrong', seem not to express subjective desires or preferences. On the other hand, they are not like ordinary factual statements, such as 'Stealing is common'. However, we do not offer straightforward empirical evidence to prove them as we do with other facts.

Judgments on traffic violations are in the same boat. Stating that 'Speeding is wrong' likewise seems to be making a factual judgment. We accept its wrongness independently of a driver's personal preference for speeding or not. In addition, both moral laws and traffic laws are grounded in facts about what makes for optimal mutual benefit. 'Speeding is wrong' is justified by the fact that speeding puts at great risk the safety of other road users. There is also a fact of the matter about which is the optimal speed limit for a particular stretch of road. This grounding in a fact about safety and efficiency explains why we do not leave driving speed up to the personal preference of each driver.

The role of facts in moral judgments is equally unremarkable. The moral law, 'Stealing is wrong', is not a matter of personal whim. Again, there is a fact of the matter about which rules regarding the transfer of property work best for a community.

For some laws, there is genuine disagreement because of uncertainty over the relevant facts. Which is the optimal speed limit for a given street may be indeterminable to some degree. In those cases, for the sake of practicality, the traffic authority legislates one particular speed within a reasonable range. Likewise for moral laws. For example, the optimal law for the compulsory acquisition of private property may also lie within a known range of options. In the face of this uncertainty, each community will enforce one set of criteria in deference to other reasonable options. A naturalist account explains the importance of reason and appeals to facts in both cases without the metaphysician's recourse to amorphous supernatural entities or transcendent dimensions.

1. 3.
   Moral laws are categorical.

Moral obligations, such as 'You ought not torture babies', are unconditional, applying whatever the person's desires, aims and objectives. In that respect, they seem unlike conditional 'oughts', such as 'If you want to get to the city, you ought to catch the next train'.

This categorical aspect of moral laws is likewise a feature of traffic laws. For example, the law of the road does not permit a driver to go through a red light even when there are no other cars or people around. The same is the case with speed limits. Even when it is safe to drive over the speed limit in a particular circumstance, the traffic rules bar drivers from maximizing benefit in that situation.

Everyone getting the advantages of the traffic control system requires barring drivers from deciding at each red light and speed sign they encounter whether road safety and driving efficiency is optimized by disobeying the law in that instance. Allowing motorists to make their own calculations of overall benefit when faced with the option of breaking a road rule will destabilize the traffic control system as a whole.

In the same way, the benefits of the system of moral rules are lost if each person is permitted to decide on a case-by-case basis when to obey the rules and when not. For example, the practice of promising will wither away if promise-makers are permitted to decide on a case-by-case basis when to break a promise for overall advantage.

The practice of rationing scarce resources is another example. At a time of water rationing, citizens are not permitted secretly to use more water than the rationed amount even in cases where doing so will increase overall benefit. Morally permitting each citizen to decide on a case-by-case basis will undermine the integrity of the rationing system, to the detriment of everyone. As a more extreme example, our sense of security will be lost if it is permitted for each person to decide for themselves when killing another in secret is overall advantageous.

This deontological aspect of moral laws is likewise a natural feature of our traffic laws. In neither case do we need to search for some deep metaphysical justification for our duty to conform to the law. Our sense of obligation is the natural outcome of wanting the benefits of living in communities in which we can rely on others.

1. 4.
   Moral laws are universal.

Moral obligations, such as 'Do not kill an innocent person', apply to all people at all locations and at all times—past, present and future. This universality of moral laws contrasts with the contingency of other rules, such as the rules of etiquette. The rule to leave shoes outside, for example, only applies in certain countries, such as Japan.

Traffic laws are at least as universal as moral laws. First, the universality of moral laws is qualified. Moral rules seem to vary at least as much from region to region as traffic rules. Moral rules regulating suicide, apostasy, use of force, property, abortion, sex, marriage and every other substantive life issue, vary from strict prohibition to permissibility from one region to another. Even universal moral rules, such as 'Do not kill an innocent person' and 'Do not steal', are interpreted radically differently in different regions and times. In some regions, a foetus is a 'person' while in others not. In some regions, an apostate and a heathen are not considered 'innocent', in others they are. In some moral codes, government-imposed tax is considered theft. In others, private property is regarded as theft.

Where there is undoubted universality in moral rules, there is likewise in traffic rules. Beyond the general moral maxims enunciated in the Golden Rule and the prohibitions on killing, stealing, lying and breaking promises, the clearest exemplification of well-specified moral rules is the 30 Articles contained in the Universal Declaration of Human Rights (see United Nations [1948]). Adopted by the United Nations General Assembly towards the end of 1948, this was a crowning achievement of a globally agreed set of moral strictures.

This universality is likewise a feature of traffic rules. Building on the 1949 Geneva Convention on Road Traffic, the Vienna Convention on Road Traffic (see United Nations [1968a]) is an international treaty ratified at the United Nations Economic and Social Council's Conference on Road Traffic in late 1968. The treaty serves to facilitate international road traffic and to increase road safety by establishing standard traffic rules. Signed at the same time and superseding the 1909 International Convention on Motor Traffic, the Vienna Convention on Road Signs and Signals (see United Nations [1968b]) established the international standard for signing systems for road traffic.

The universalizing of traffic rules towards global standards has a natural explanation. The causes for this are the increasing interconnectedness of nation states through trade, travel and immigration coupled with similar fundamental pan-continental roadway structures, automobile design and driver characteristics. In like fashion, no recourse to gods or some transcendental realm is needed to explain the universality of moral laws. Both systems are grounded in basic facts about human nature, universal human needs and the increasing interconnectedness of human societies.

1. 5.
   Moral agents act with virtue.

Moral judgments apply not only to the veracity of certain laws, but also to the character of moral agents. A person is considered 'good' if they act with the right intention. A philanthropist who donates to a good cause, for example, is not thought to be acting morally if they donated primarily for self-promotion. The role of moral education is the inculcation of virtues such as charity, courage and justice. A virtuous person is one who has developed the psychological disposition—the habit—to act rightly in a variety of circumstances.

The role of virtue is no different in our traffic control system, playing just as important a function. A key purpose of driver education is to inculcate driver behaviours that are automatic. For example, driver training teaches students to stick to the designated side of the road, to watch their speed and to observe traffic signage. Training is designed to build the right kind of character traits—the right habits—required for driving safely on the road. Allied with the deontological nature of moral laws and traffic laws, it works to everyone's advantage if people keep their promises and keep to the speed limit out of habit, without deliberating each time over whether doing so maximizes benefit in that instance.

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Here, I have identified the five essential characteristics of our system of morals and compared them with our system of traffic laws. What seemed to metaphysicians to be mysterious features of morality requiring appeal to a supernatural realm turn out to be natural elements found equally in the traffic control system. If a naturalist account explains adequately the normativity of road rules, how they are grounded in facts about human co-operation, their unconditional and universal scope and the importance of good character (as it surely does), then we can equally do without obscure metaphysical explanations for our system of moral rules. Just as no spooky metaphysics is required to underwrite our obligation to obey road laws, likewise for our duty to obey moral laws.

Copyright © 2026 Leslie Allan