Rudyard Kipling wrote a small poem
Page 65 Rudyard Kipling wrote a small poem. “I keep six honest man, they taught me all I know,. Their names are what and why and when and how and where and who. Let us imagine that you meet someone and are beginning to think that they may be your life partner , those questions would be most appropriate now.
— from The Mind in the Cockpit · 21 letters on life and its challenges by Charles handy
In the book
But also learn useful thinking: distinguish what is actually worth your thought from what is not, and refuse to spend the instrument on noise. Run a thinking checklist, and keep good company. Borrow Kipling's six honest servants — what, why, when, how, where, and who — and let them interrogate any hard problem. Seek out the people who challenge your thinking, because you learn far more from them than from the ones who only agree with you; remember Patton's line that if everyone is thinking alike, then somebody isn't thinking. — The Mind in the Cockpit