--- title: "Meaning & Key Takeaway of: To begin with rationality in opinion: I…" description: "\"“To begin with rationality in opinion: I should define it merely as the habit of taking account of all relevant evidence in arriving at a belief. Where..." image: "https://sms4smile.com/quotes/i/338/bertrand-russell-69_doubt_to-begin-with-rationality-in-opinion-i-s_2347178.jpg" --- # To begin with rationality in opinion: I should define it… ![“To begin with rationality in opinion: I should define it merely as the habit of taking account of all relevant evidence in arriving at a belief. Where certainty is unattainable, a rational man will give most weight to the most probable opinion, while retaining others, which have an appreciable…” quote by Bertrand Russell](https://sms4smile.com/quotes/i/338/bertrand-russell-69_doubt_to-begin-with-rationality-in-opinion-i-s_2347178.jpg) [Download](https://sms4smile.com/quotes/i/338/bertrand-russell-69_doubt_to-begin-with-rationality-in-opinion-i-s_2347178.jpg) [Open image](https://sms4smile.com/quotes/i/338/bertrand-russell-69_doubt_to-begin-with-rationality-in-opinion-i-s_2347178.jpg) > ““To begin with rationality in opinion: I should define it merely as the habit of taking account of all relevant evidence in arriving at a belief. Where certainty is unattainable, a rational man will give most weight to the most probable opinion, while retaining others, which have an appreciable probability, in his mind as hypotheses which subsequent evidence may show to be preferable.”” [Bertrand Russell](https://sms4smile.com/quotes/author/bertrand-russell/) ## About This Quote This interpretation was drafted with AI assistance. It is one reading of the quote, not the author's own explanation. Rationality means weighing all evidence, favoring the most probable belief while keeping alternative hypotheses for future evidence. **In simple terms:** Rationality is evidence‑based belief with openness to alternatives. Key Takeaway Base decisions on evidence, stay open to new data. Themes evidence probability open‑mindedness Mood analytical thoughtful Type philosophical educational When to use this quote - scientific research - legal judgments - medical diagnosis - investment analysis Key Concepts philosophy epistemology critical thinking Questions to Reflect On - How do you ensure you consider all relevant evidence? - When should you revise a belief? A Different Perspective Rationality can be limited by cognitive biases and incomplete data. ★ ★ ★ ★ ★ No ratings yet [Begin Rationality](https://sms4smile.com/quotes/about/begin-rationality-5701441/) [Belief Certainty](https://sms4smile.com/quotes/about/belief-certainty-1515905/) [Doubt](https://sms4smile.com/quotes/about/doubt/) [Faith](https://sms4smile.com/quotes/about/faith/) [Habits](https://sms4smile.com/quotes/about/habits/) [Irrational](https://sms4smile.com/quotes/about/irrational/) [Opinion Define](https://sms4smile.com/quotes/about/opinion-define-4738212/) [Rationality](https://sms4smile.com/quotes/about/rationality/) [Rationality Opinion](https://sms4smile.com/quotes/about/rationality-opinion-1329901/) ## Related quotes > [“Pragmatism emphasizes the irrationality of opinion, and psycho-analysis emphasizes the irrationality of conduct. 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