“The process of philosophizing, to my mind, consists mainly in passing from those obvious, vague, ambiguous things, that we feel quite sure of, to something precise, clear, definite, which by reflection and analysis we find is involved in the vague thing that we start from, and is, so to speak, the real truth of which that vague thing is a sort of shadow.”

If some one speaks of a spiritual fact as "indefinable" we promptly picture something misty, a cloud with indeterminate edges. But this is an error even in commonplace logic. The thing that cannot be defined is the first thing; the primary fact. It is our arms and legs, our pots and pans, that are indefinable. The indefinable is the indisputable. The man next door is indefinable, because he is too actual to be defined. And there are some to whom spiritual things have the same fierce and practical proximity; some to whom God is too actual to be defined.
Ch 1 : "The Dickens Period"
Charles Dickens (1906)

Source: Sister Carrie

Sense and Sensibilia (1962), p. 125

Variant: How true it is that words are but the vague shadows of the volumes we mean. Little audible links, they are, chaining together great inaudible feelings and purposes.
Source: Sister Carrie

Source: 1910s, Our Knowledge of the External World (1914), p. 70

Part III, Chapter VI
Les voix du silence [Voices of Silence] (1951)

Source: Surprised by Hope: Rethinking Heaven, the Resurrection, and the Mission of the Church

Herman E. Daly and Joshua Farley, in Ecological Economics: Principles and Applications. (2003), page 234. quoted in Beyond GDP Measuring progress, true wealth, and the well-being of nations http://ec.europa.eu/environment/beyond_gdp/key_quotes_en.html, European Commission:Environment

Source: The Embodied Mind (1991), p. 63