Version: v1, Published online: 1998
Retrieved March 21, 2019, from https://www.rep.routledge.com/articles/thematic/practical-reason-and-ethics/v-1
Practical reason is reasoning which is used to guide action, and is contrasted with theoretical reason, which is used to guide thinking. Sometimes ‘practical reason’ refers to any way of working out what to do; more usually it refers to proper or authoritative, hence reasoned, ways of working out what to do.
On many accounts practical reasoning is solely instrumental: it identifies ways of reaching certain results or ends, but has nothing to say about which ends should be pursued or which types of action are good or bad, obligatory or forbidden. Instrumental reasoning is important not only for ethics and politics, but for all activities, for example, in working out how to travel to a given destination.
Other accounts of practical reason insist that it is more than instrumental reasoning: it is concerned not only with working out how to achieve given ends, but with identifying the ethically important ends of human activity, or the ethically important norms or principles for human lives, and provides the basis for all ethical judgment.
No account of objective ethical values can be established without showing how we can come to know them, that is, without showing that some form of ethical cognitivism is true. However, ethical cognitivism is not easy to establish. Either we must show that some sort of intuition or perception provides direct access to a realm of values; or we must show that practical reasoning provides less direct methods by which objective ethical claims can be established. So anybody who thinks that there are directly objective values, but doubts whether we can intuit them directly, must view a plausible account of practical reason as fundamental to philosophical ethics.
O'Neill, Onora. Practical reason and ethics, 1998, doi:10.4324/9780415249126-L073-1. Routledge Encyclopedia of Philosophy, Taylor and Francis, https://www.rep.routledge.com/articles/thematic/practical-reason-and-ethics/v-1.
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