IB Philosophy 1.5.3 Emotion and Reason Notes

Reason as the Defining Human Characteristic

1. Topics 1.5.1 and 1.5.2 examined whether humans share a common nature and how fixed or malleable that nature is. This final topic in the Human Nature sub-theme turns to a specific question: what is the relationship between emotion and reason, and is reason what distinguishes human beings from other animals and from machines?
2. The IB syllabus asks: "Is reason a special characteristic that distinguishes humans from machines or other animals?" This question connects to 1.4.2 (Agency), where we examined whether animals and machines could be considered persons.
3. If reason is uniquely human, it may ground a fundamental distinction between humans and all other beings.
4. René Descartes provided the most influential philosophical defence of reason as the defining human characteristic. In the Discourse on the Method, Descartes argued that the capacity for rational thought is what separates human beings from animals, which he regarded as complex machines (automata: biological robots that follow fixed biological rules) with no genuine understanding.
5. For Descartes, the evidence that animals lack reason comes from two observations: animals never use language to express genuine thoughts, and they never act with the flexible intelligence that reason provides.
6. A parrot can mimic words, but it cannot compose original sentences. An animal can perform complex tasks, but only through instinct, not through rational deliberation.
7. Descartes connected reason to the immaterial soul. Because reason cannot be reduced to mechanical processes, Descartes concluded that humans possess a non-physical mind (what he called res cogitans, or 'thinking thing') that is the seat of thought.
8. This is Descartes' dualist position (explored in 1.3.2): since reason cannot be reduced to gears and mechanisms, it must belong to a fundamentally different kind of thing than the physical body, what Descartes called the immaterial mind.

Aristotle, Kant, and the Moral Foundation of Reason

1. Aristotle had earlier identified reason as the distinctive human function. In the Nicomachean Ethics, Aristotle argued that while plants have a nutritive soul and animals have a sensitive soul, only humans possess a rational soul.
2. Human flourishing (eudaimonia, meaning living and doing well as a human being) consists in actually exercising our rational capacity, and doing it well, through the practice of virtue.
3. Immanuel Kant elevated reason even further. In the Groundwork of the Metaphysics of Morals, Kant argued that reason is not merely what distinguishes humans but what gives them moral dignity.
4. Only rational beings can understand and follow the moral law. This capacity makes persons ends in themselves, never merely means.
5. Reason, for Kant, is the foundation of morality itself.
6. Consider a shopkeeper who gives correct change to a child. If the shopkeeper acts honestly only because dishonesty would damage their reputation (a self-interested calculation), they act in accordance with duty but not from duty.
7. Kant argues that genuine moral worth requires acting from respect for the moral law itself, treating the child as an end, never merely as a means. This capacity for principled action, grounded in reason alone, is what gives human beings their unique dignity.

The Stoics and the Challenge from Artificial Intelligence

1. The Stoic tradition provides another defence of reason's supremacy. The Stoics, including Epictetus and Marcus Aurelius, argued that the good life consists in living according to reason and accepting what is beyond our control.
2. Emotions (passions) are disturbances that arise from mistaken ways of seeing the world, false judgements, and should be brought under rational control.
3. Epictetus, himself a former slave, illustrates the Stoic ideal: ‘It is not things that disturb us, but our judgements about things.’ When insulted, a Stoic does not suppress anger through willpower but dissolves it by recognising that the insult has no power unless one judges it harmful.
4. Marcus Aurelius, writing in his Meditations while commanding Roman legions on the frontier, counsels himself to meet each morning’s annoyances, ‘the meddling, the ungrateful, the arrogant’, with the rational recognition that such people act from ignorance, not malice.
5. These rationalist views share a common assumption: that reason is superior to emotion and that the properly human life is one governed by rational thought. Emotions, on this view, are either obstacles to clear thinking or, at best, raw material that reason must discipline and direct.
6. However, recent developments in artificial intelligence challenge the assumption that reason is uniquely human. As discussed in 1.4.2 (Agency), machines can now perform many tasks previously thought to require rational intelligence: playing chess, composing text, solving mathematical problems.
7. If machines can reason, then reason alone may not be sufficient to distinguish humans from machines, a point that strengthens the case for examining emotion as equally central to human nature.