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Amsterdam, April 3 1878

I have been thinking over what we have been talking about and involuntarily I thought of the saying, "nous sommes aujourd'hui ce que nous étions hier." That does not mean that one must stand still and may not try to develop oneself, on the contrary there is an urgent reason for doing so and succeeding in it. But in order to remain true to that saying one must not slide back and if one has begun to look at things in a free and open ay, one must not give it up or deviate from it.
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Letters of Vicent Van Gogh.