William Benjamin Carpenter MD MRCS CB FRS (29 October 1813 – 19 November 1885) was an English physician, invertebrate zoologist and physiologist. He was instrumental in the early stages of the unified University of London.

Carpenter was born on 29 Oct 1813 in Exeter, the eldest son of Dr Lant Carpenter, an important Unitarian preacher who influenced a "rising generation of Unitarian intellectuals". From his father, Carpenter inherited a belief in the essential lawfulness of the creation: this meant that natural causes were the explanation of the world as we find it. William embraced this "naturalistic cosmogeny" as his starting point.

Although qualified medically, he was best known for his work on marine zoology, notably the lower organisms such as Foraminifera and crinoids. These researches gave an impetus to deep-sea exploration, such as the 1868 oceanographic survey with HMS Lightning and later the more famous Challenger Expedition.

In the long term, however, he has become known as a founder of idea of the adaptive unconscious. He observed that the human perceptual system almost completely operates outside of conscious awareness. These same observations were also made by Hermann Helmholtz. Perhaps because these views were in conflict with the theories of Descartes, they were neglected for a hundred years. Carpenter noticed that the more he studied the mechanism of thought, the more clear it became that it operates largely outside awareness. He noticed that the unconscious prejudices can be stronger than conscious thought and that they are more dangerous since they happen outside of conscious.
He also noticed that emotional reactions can occur outside of conscious until attention is drawn to them:
"Our feelings towards persons and objects may undergo most important changes, without our being in the least degree aware, until we have our attention directed to our own mental state, of the alteration which has taken place in them".
He also asserted both the freedom of the will and the existence of the ego.

In the popular mind, he was perhaps better nown for his work against alcoholism, for which he won a prize of 100 guineas. It was one of the first temperance books.

In 1856 Carpenter became Registrar of the University of London, and held the office for twenty-three years. He was made a Companion of the Order of the Bath.

Works 
Carpenter, William Benjamin 1839. Principles of general and comparative physiology. London. 
Carpenter, William Benjamin 1842 [first edition]; 1843 [first American edition]. Principles of human physiology. London and Philadelphia. 
Carpenter, William Benjamin 1844. Vegetable and systematic botany. London: Orr.
Carpenter W.B. 184445. Zoology: being a systematic account of the general structure, habits, instincts and uses of the principal families of the animal kingdom. 2 vols: London: Rees.
Carpenter, William B. 1848. Animal physiology. 2nd ed, London: Wm. S. Orr, p. 579. The first edition was 1843, dedicated to Sir James Clark.
Carpenter, William Benjamin 1850. Condie, David Francis, ed. On the use and abuse of alcoholic liquors, in health and disease. London: Churchill.
Carpenter, William Benjamin 1852. On the influence of suggestion in modifying and directing muscular movement, independently of volition. Proceedings of the Royal Institution of Great Britain: 147–153.
Carpenter W.B. 1856. The microscope and its revelations. London: Churchill.
Carpenter, William Benjamin 1862. Introduction to the study of Foraminifera. London: Ray Society.
Carpenter, William Benjamin 1874. Principles of mental physiology. London: Henry S. King. (facsimile by Thoemmes Press 1998. ; reissued by Cambridge University Press 2009. ).
Carpenter, William Benjamin 1887. Mesmerism, spiritualism, etc: historically and scientifically considered. New York: Appleton.
Carpenter, William Benjamin & Carpenter, J. Estlin 1888. Nature and man: essays scientific and philosophical. London: Kegan Paul & Trench. A posthumous collection of his writings in periodicals.

References 

1813 births
1885 deaths
English biologists
English physicians
British physiologists
Unitarians