“All knowledge is to some extent interpreted.”

MovNat: Learning how to move as we were intended to, The Washington Post http://washingtonpost.com/lifestyle/wellness/movnat-learning-how-to-move-as-we-were-intended-to/2012/02/03/gIQABjNMRR_story.html?utm_term=.e68f6050d5d7_r=0

On the Uses and Transformations of Linear Algebra (1875)
Context: The familiar proposition that all A is B, and all B is C, and therefore all A is C, is contracted in its domain by the substitution of significant words for the symbolic letters. The A, B, and C, are subject to no limitation for the purposes and validity of the proposition; they may represent not merely the actual, but also the ideal, the impossible as well as the possible. In Algebra, likewise, the letters are symbols which, passed through a machinery of argument in accord ance with given laws, are developed into symbolic results under the name of formulas. When the formulas admit of intelligible interpretation, they are accessions to knowledge; but independently of their interpretation they are invaluable as symbolical expressions of thought. But the most noted instance is the symbol called the impossible or imaginary, known also as the square root of minus one, and which, from a shadow of meaning attached to it, may be more definitely distinguished as the symbol of semi-inversion. This symbol is restricted to a precise signification as the representative of perpendicularity in quaternions, and this wonderful algebra of space is intimately dependent upon the special use of the symbol for its symmetry, elegance, and power.

From his speech given on 28 November 1960 at laying the foundation-stone of the building of the Law Institute of India, in: p. 16
Presidents of India, 1950-2003

These words, sometimes attributed to Addison, are not found in his works, but in The Spectator, no. 54, he translates the following words of Socrates, as quoted in Plato's Apology: "When I left him, I reasoned thus with myself: I am wiser than this man, for neither of us appears to know anything great and good; but he fancies he knows something, although he knows nothing; whereas I, as I do not know anything, so I do not fancy I do. In this trifling particular, then, I appear to be wiser than he, because I do not fancy I know what I do not know."
Misattributed

The Interpretation of Dreams (1900), from The Standard Edition of the Complete Psychological Works of Sigmund Freud, translated by James Strachey.
At any rate the interpretation of dreams is the via regia to a knowledge of the unconscious in the psychic life.
Alternate translation by Abraham Arden Brill, p. 483 http://books.google.com/books?id=OSYJAAAAIAAJ&pg=PA483#v=onepage&q&f=false. Freud did use the Latin phrase via regia in the original as opposed to translating it into the German of the surrounding text.
"Royal road" or via regia is an allusion to a statement attributed to Euclid.
1900s

Source: Kafka on the Shore