RUTH BARCAN MARCUS AND MODALITY (10): Adjusting Rationality

Marcus now asks whether our usual picture of rationality needs to be adjusted. Marcus does not want to throw away the idea of rationality. She wants to improve it. She thinks that many traditional theories of rationality are too narrow, too idealised, and do not match how real people think, act, decide, and believe. So she proposes several revisions, which means she offers new suggestions about how to understand rationality in a more accurate and humane way.

She begins with a simple observation. Traditional models of rationality often assume that a perfectly rational person is someone who always follows strict rules. These rules focus mostly on avoiding contradictions and making precise deductions. Marcus thinks this picture is incomplete. It ignores moral commitments, emotional involvement, personal understanding, and practical needs. It also ignores the fact that real people face limited information, limited time, and genuine conflicts of duty. A theory of rationality that tries to be perfect by ignoring reality is not helpful. Her first proposal is that rationality should be understood as responsive, not rigid. A rational person is someone who responds appropriately to reasons. This includes logical reasons, moral reasons, practical reasons, and emotional reasons that reflect genuine values. A rigid person who never changes their mind is not more rational. A rational person must be open to new evidence, new arguments, and new perspectives. This connects to her earlier idea that belief requires courage. True rationality includes the willingness to revise one’s view.

Next she argues that rationality must leave room for commitments, the deep principles that shape a person’s life. In earlier chapters she explained how commitments narrow the space of actions that a person genuinely sees as possible. Now she says that commitments are not irrational restrictions. Instead they are part of what makes reasoning stable. They help guide decisions when evidence is incomplete. They give shape to the person’s moral identity. A theory of rationality that treats commitment as a flaw misses the fact that commitments help people structure their lives. She then turns to the question of conflict, both moral conflict and practical conflict. Many classical theories of rationality assume that a perfectly rational agent never experiences real conflict, because everything is neatly ordered and there is always one best choice. Marcus says this is false to experience. People often face situations where two important values pull in opposite directions. A good theory of rationality must recognise that conflict is part of human life. It must allow that a person can hold two genuine “oughts” at the same time, even if they cannot satisfy both. Rationality does not require perfect harmony. It requires clarity and honesty about the difficulty.

She then revisits the idea of coherence. Traditional logical theories picture coherence as strict consistency: never believing anything that contradicts something else you believe. Marcus agrees that coherence matters, but says it must be interpreted realistically. Real people often discover inconsistencies in their beliefs only when the problem becomes obvious. We live with inconsistencies all the time.  Rationality is not the absence of inconsistency. It is the capacity and willingness to repair inconsistencies when they are noticed. Coherence then becomes an ongoing activity rather than a static condition. Marcus then expands the picture by discussing practical reasoning, the kind of thinking used when making decisions. She says practical reasoning must not be separated from theoretical reasoning. They are parts of the same rational life. Practical reasoning involves figuring out what actions would best express your commitments and beliefs. It also requires understanding the consequences of actions, which draws on logical inference. This shows that rationality extends across both belief and action.

She offers another revision: rationality should be understood as involving sensitivity to reasons that matter, not just reasons that are mechanically valid. A child might learn a rule like “If A then B,” but rationality is more than applying rules. It includes understanding which facts are relevant to a question, which considerations have moral weight, which experiences matter, and which explanations are genuine. Rationality is intelligent attention, not just rule following. She also wants to correct a mistake found in some theories of rational choice. These theories say that rational agents always try to maximise some single goal, such as happiness or efficiency. Marcus thinks this is far too simple. People have many goals that cannot always be placed on one scale. They care about friendship, fairness, truthfulness, dignity, curiosity, and many other things. Rationality involves navigating among multiple goals, not reducing everything to one master value. A rational person sometimes sacrifices one good thing to protect another. This is not a failure but clearly could lead in some to feelings of regret and judging the universe as tragic. All this is part of what it means to be a moral agent. In the light of this feelings seem to be part of rationality.

Some theories of rationality treat emotions as enemies of reason. Marcus strongly rejects this view. She says emotions can express values, reveal what matters, and alert us to moral dimensions of situations. Fear, regret, guilt, admiration, and empathy all carry information. A theory of rationality that treats emotions as irrelevant or dangerous leaves out an essential part of human understanding. Rationality does not silence emotion. It interprets it. She then links all these proposals back to the unity of reason. A good theory of rationality must be wide enough to include logical inference, moral commitment, belief revision, practical decision making, emotional understanding, and sensitivity to context. These are not separate engines operating in isolation. They are aspects of one unified ability. Each influences the others. A rational person uses this unity to make sense of their life and their relationships.

She explains why these revisions matter. Without them, theories of rationality become unrealistic, and unrealistic theories misdescribe human agency. They also often end up blaming individuals for things that are inevitable, such as facing moral conflicts or having to choose under uncertainty. Marcus thinks a humane theory of rationality should recognise the real conditions under which people think and act. She presents rationality as a kind of practical wisdom. It is not perfection. It is not rigid consistency. It is the ability to think well, feel honestly, revise responsibly, and act with integrity in the face of incomplete knowledge and conflicting demands. Rationality is the power to live thoughtfully.

She thinks that these revisionary proposals do not weaken rationality. They strengthen it. They make rationality something that real people can possess and aspire to. They draw together logic, morality, belief, and action into a single picture of what it means to be a competent and reflective agent.