BR TO PHILIP E.B. JOURDAIN, 2 JAN. 1911
BRACERS 53360. ALS. Mittag-Leffler Institute. Dear Russell—Dear Jourdain, pp. 136–7
Proofread by K. Blackwell

<letterhead>
Telegraph House,
Chichester.1
Jan. 2. 1911

Dear Jourdain

Many thanks for your letter and notes of misprints. If you find any others, I shall be glad to know of them. I don’t see the force of your point about the Df of V. The Df of $\hat{x}$(φx) depends on φ, and if φ is variable, so is $\hat{x}$(φx). But when we put

V = $\hat{x}$(x = x) Df,

φ is constant, and thus V is constant.

Yes, the Df of $\overrightarrow{R}$‘x on p. 34 is just as wrong as the Df of Cnv‘R, but I remarked over Cnv‘R that in the Introduction I was going to ignore this. The wrongness does not consist in being under a hp, but in the fact that “Cnv” or “$\overrightarrow{R}$” ought to be defined by itself.

As for the omission on p. 98, that hangs together with the theory of types. I no longer think it significant to deny x ⊃ q, where x is not a prop. I think that, strictly, one ought not to use a single letter for a prop, but always some such symbol as φx. But so long as this is remembered, it is not necessary always to do what strictly ought to be done.

I am sorry I have no copy of my article in the Internat. Monthly,2 and I have not reprinted the article, as I found I should have to spoil the jokes to bring it up to date. The only person I know of who has a copy is Miss Jane Harrison, Newnham College, Cambridge. I dare say she would lend you her copy. (She is the archeologist.)

I am much relieved to hear that in writing on Boole you acted on “higher guidance”. I had heard Mrs B. was indignant at the suggestion that symbolic logic was the subject of her husband’s book.

Yrs ever
Bertrand Russell.

• 1

  [document] Proofread against a printout of the microfilm of the original letter and compared with Dear Russell — Dear Jourdain.

• 2

  Internat. Monthly “Recent Work on the Principles of Mathematics”, The International Monthly, 4 (July 1902): 83–101. BR reprinted it as “Mathematics and the Metaphysicians”, Mysticism and Logic (1918). It is 10 in Papers 3.