Observation statements are based on unconscious theorizing (says Sir George Lewis in 1849)

Sir George Cornewall Lewis, 'Essay on the Influence of Authority in Matters of Opinion' (1849):

It is true that even the simplest sensations involve some judgment: when a witness reports he saw an object of a certain shape and size, or at a certain distance, he describes more than a mere impression of his sense of sight, and his statement implies a theory and explanation of the bare phenomenon. When, however, this judgment is of so simple a kind as to become wholly unconscious, and the interpretation of the appearances is a matter of general agreement, the object of sensation may, for our present purpose, be considered a fact.