Ethical theories provide frameworks for analysing moral situations. Engineers use these frameworks — often implicitly — when making design, safety, and professional decisions.
Major Ethical Theories
| Theory | Core Principle | Key Figure | Engineering Relevance |
| Consequentialism / Utilitarianism | Action is right if it produces the greatest good for the greatest number | Bentham, Mill | Cost-benefit analysis, risk assessment |
| Deontology | Duty-based ethics — some acts are intrinsically right/wrong regardless of consequences | Kant | Absolute safety obligations, not to deceive client |
| Virtue Ethics | Focus on character of the agent rather than rules or outcomes | Aristotle | Professional character, integrity, competence |
| Rights-based Ethics | All persons have fundamental rights that must be respected | Locke, Rawls | Worker rights, community right-to-know |
| Contractarianism | Morality derives from social contracts and agreements | Hobbes, Rawls | Professional codes as social contracts |
| Care Ethics | Emphasises relationships, empathy, and contextual caring | Gilligan, Noddings | Stakeholder engagement, community impact |
Utilitarianism in Detail
- Act utilitarianism: Evaluate each act individually by its consequences
- Rule utilitarianism: Follow rules that, if generally adopted, produce best outcomes
- Application: Risk analysis, trade-offs between cost and safety, ALARP principle (As Low As Reasonably Practicable)
Kantian Deontology — Categorical Imperative
Act only according to that maxim by which you can at the same time will that it should become a universal law.
- Formula of Humanity: Treat persons as ends in themselves, never merely as means
- Application: Engineers must not deceive clients even if deception would avoid panic
Rawls' Theory of Justice
- Veil of ignorance: Design principles without knowing your position in society
- Difference principle: Inequalities are just only if they benefit the least advantaged
- Application: Infrastructure decisions that serve disadvantaged communities equitably
Limits of Each Theory
| Theory | Strength | Limitation |
| Utilitarianism | Practical; considers all outcomes | Can justify harming minority for majority benefit |
| Deontology | Protects individual rights; clear rules | Rigid; can produce bad outcomes in extreme cases |
| Virtue ethics | Holistic; develops character | Less guidance in novel dilemmas |
| Rights-based | Protects individuals | Rights can conflict with each other |
ESE Tip: Be able to apply multiple frameworks to a scenario. Questions often ask: "Which ethical theory best explains...?" Know the key terms: categorical imperative, veil of ignorance, ALARP, greatest good.