Full Idea
Nobody can really doubt that there are Reals, for, if he did, doubt would not be a source of dissatisfaction.
Clarification
By 'Reals' he means an external reality
Gist of Idea
If someone doubted reality, they would not actually feel dissatisfaction
Source
Charles Sanders Peirce (The Fixation of Belief [1877], p.19)
Book Reference
Peirce,Charles Sanders: 'Philosophical Writings of Peirce', ed/tr. Buchler,Justus [Dover 1940], p.19
A Reaction
This rests on Peirce's view that all that really matters is a sense of genuine dissatisfaction, rather than a theoretical idea. So even at the end of Meditation One, Descartes isn't actually worried about whether his furniture exists.