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Darwin Correspondence Project

To James Torbitt   26 January 1876


Jan. 26, 1876.

My dear Sir

I am much obliged for the Belfast Journal, which I will look to. It is, I believe, almost impossible to answer your question.— “what makes an Individual?”1 Naturalists are generally agreed to look at all the members produced by one act of sexual generation as belonging to the same individual, but this definition will not apply to some of the lowest organisms which multiply by self division, but not as far as known by sexual generation.2 How it is that a single cell, or a very few cells, suffice to give rise to a new organism will never be known until we can say what life is, and we are at present a long way off this goal. I wish I could have answered your question better.

Dear Sir | Yours faithfully | Chas. Darwin

J. Torbitt, Esq. | Belfast.


See letter from James Torbitt, 24 January 1876. Torbitt had enclosed a copy of his paper ‘Potato cultivation’ from the Proceedings of the Belfast Natural History and Philosophical Society (Torbitt 1875).
The definition of an individual as the entire product of a single sexually fertilised ovum had been championed by Thomas Henry Huxley (Elwick 2007, pp. 133–4). For CD’s adherence to the idea of independence as the defining characteristic of an individual organism, see Correspondence vol. 5, letter to T. H. Huxley, 17 July [1851].


Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 27 vols to date. Cambridge: Cambridge University Press. 1985–.

Elwick, James. 2007. Styles of reasoning in the British life sciences: shared assumptions, 1820–1858. London: Pickering & Chatto.

Torbitt, James. 1875. Potato cultivation. [Read 14 April 1875.] Proceedings of the Belfast Natural History and Philosophical Society (1874–5): 112–25.


Obliged for Belfast Journal.

Almost impossible to determine what constitutes an individual. Definition for sexually reproducing organisms does not apply to lower ones.

Letter details

Letter no.
Charles Robert Darwin
James Torbitt
Sent from
Source of text
DAR 148: 91
Physical description

Please cite as

Darwin Correspondence Project, “Letter no. 10368,” accessed on 4 March 2021,

Also published in The Correspondence of Charles Darwin, vol. 24