Book by Mark L. Morrissey
On certainty, evidence, and the courage to be wrong.


This book asks a deceptively simple question: what evidence would be enough to make us reconsider something we feel certain about?
For the Practical Retiree Lab audience, the topic is central. Good retirement decisions, good science, and good use of AI all require the same discipline: separating confidence from evidence.
Available on Amazon as Kindle eBook and paperback.
Why it belongs here
This site is aimed at retirees who want useful, serious, non-hyped guides for learning, reasoning, technology, science, and practical decision-making.
Return to the homepage