“The man who has no tincture of philosophy goes through life imprisoned in the prejudices derived from common sense, from the habitual beliefs of his age or his nation, and from convictions which have grown up in his mind without the co-operation or consent of his deliberate reason.”
Unexamined common sense can become a prison when inherited assumptions are accepted automatically instead of being tested by deliberate reasoning.
Source details
The Problems of Philosophy, Chapter XV, “The Value of Philosophy,” beginning on printed page 242 / scan leaf 246 and continuing onto printed page 243 / scan leaf 247 in the fully validated 1912 Williams & Norgate Wikisource scan, cross-checked against Project Gutenberg #5827. The “no tincture of philosophy” sentence criticizes inherited common-sense, national and habitual prejudices that have not been examined by deliberate reason; it remains Russell’s philosophical argument rather than a diagnosis of people who do not study philosophy.