a. Meaning: ‘prikkelt’ (stimulates, spurs).

1. This is letter 188.

2. Van Gogh later added the sentence ‘(Let us... Mauve)’.

3. A reductio ad absurdum is ‘a method of proving the falsity of a premiss, principle, etc., by showing that the conclusion or consequence is absurd’ (OED).

b. Meaning: ‘grondstelling’, ‘uitgangspunt’ (basic principle).

4. Cf. Matt. 6:22 and Luke 11:34.

5. In Sund’s opinion this passage indicates knowledge of Zola’s essay ‘Le moment artistique’, published in Mes haines. See Sund 1992, pp. 53-54. Zola’s book is first mentioned, however, in letter 358. Moreover, Van Gogh puts the work and the author on the same plane, whereas Zola puts the author first.