Full Idea
Metaphysics really rests on observations, whether consciously or not. The only reason this is not recognised is that it rests upon kinds of phenomena with which every man's experience is so saturated that he pays no particular attention to them.
Gist of Idea
Metaphysics rests on observations, but ones so common we hardly notice them
Source
Charles Sanders Peirce (The Approach to Metaphysics [1898], p.311)
Book Reference
Peirce,Charles Sanders: 'Philosophical Writings of Peirce', ed/tr. Buchler,Justus [Dover 1940], p.311
A Reaction
I think this is entirely right. I would say that the only thing that distinguishes metaphysical thought is its extreme level of generality, which makes it very hard to substantiate, because it is so remote from its evidential base.