Edmund Duncan Montgomery, physician, scientist, philosopher, and husband of sculptor Elisabet Ney, was born in Edinburgh, Scotland, on March 19, 1835, the son of Duncan McNeill, a Scottish jurist, and Isabella Davidson Montgomery. His parents were evidently unmarried and separated shortly after his birth. At the age of four he moved to Paris with his mother, where they lived until around 1844, when they moved to Frankfurt-am-Main. Montgomery was educated by private tutors and came into early contact with the revolutionary ideas sweeping Germany at the time; at thirteen he participated in the uprising of 1848. From 1852 to 1855 he studied medicine at Heidelberg. There he joined the circle of Christian Kapp and absorbed the materialist views of Ludwig Feuerbach and Jacob Moleschott, which stimulated in him a lifelong search to solve the philosophical problems of life and mind through experimental methods. Montgomery continued his studies in Berlin (1855–56), Bonn (1856–57), and Würzburg (1857–58); he received his M.D. degree from Würzburg by state examination on February 18, 1858. He studied hospital practice and technique at Prague in 1858 and at Vienna the next year. In 1860 he became resident physician at the German Hospital and the Bermondsey Dispensary in London and was made demonstrator of morbid anatomy and curator of the museum at St. Thomas's Hospital, London; he held these positions until 1863. During this time he performed a number of microscopic experiments with various types of cells. In December 1862 he became a member of the Royal College of Physicians of London and in April 1863 was recommended to take over a vacant share of physiological lectures in St. Thomas's Hospital for the next year. But because of a tubercular infection he relinquished his connections in London on November 1, 1863. He retired to Madeira, where he married Elisabet Ney on November 7, 1863, and took up the practice of medicine. He practiced in Madeira (1863–65), Menton (1866), and Rome (1867) and moved to Munich in 1868. In 1869 he received an annuity and retired from medical practice to devote his time to scientific research, philosophical reflection, and writing.
In 1871 Ney and Montgomery immigrated to America. They settled near Thomasville, Georgia, where they purchased a farm and tried farming. Two years later they moved to Texas and, on March 4, 1873, purchased Liendo Plantation, near Hempstead. There Montgomery devoted the remainder of his life to scientific research, thinking, farming and ranching, and striving to raise the cultural level of the community. His first five years were devoted exclusively to the microscopic examination of the simplest forms of life; the next fifteen to the formulation, exposition, and defense of his scientific and philosophical views, based on his research. His essays written during this period were published in the leading scientific and philosophical journals of America, England, and Germany. In his first scientific monograph, On the Formation of So-Called Cells in Animal Bodies,published in 1867, Montgomery rejected the explanation of vital phenomena in terms of a "vital principle" and gave his own explanation in terms of the principle of "vital organization," chemical elaboration within living substance, resulting from interaction between the substance and its environment, which leads to constantly increasing intricacy and complexity of structure within the substance, the basis of all its abilities. In his next work, Die Kant'sche Erkenntnisslehre widerlegt vom Standpunkt der Empirie (1871), he attacked Immanuel Kant's theory of knowledge on the basis of its abstractness and its failure to recognize the role played by the physiological structure of the organism in the knowledge situation. His subsequent writings (1878–1911) were devoted to the extension, elaboration, and defense of the application of his "principle of explanation" to the solution of various philosophical problems.
Montgomery took an active interest in Prairie View Normal School (now Prairie View A&M University), offering advice and support to the early leaders and faculty of the school. Otherwise, however, he confined his attention to his studies and writing until the 1890s, when, prompted by domestic and economic problems, he turned somewhat from scientific and philosophic interests to the more practical pursuit of public office, farming, and ranching. He served as a Waller County road commissioner, secretary of the Melon Growers Association of Waller County, and chairman of the Democratic executive committee of Waller County. In 1895 he became a member of the Texas Academy of Science. In 1904 he summarized and published his basic scientific views in a monograph, The Vitality and Organization of Protoplasm, which he meant to serve as a scientific basis for his magnum opus, Philosophical Problems in the Light of Vital Organization, published in 1907.
In June 1907 Elisabet Ney died. Montgomery suffered an apoplectic attack two months later and was an invalid the remainder of his life, during which time he wrote his last work, The Revelation of Present Experience, published in 1911. He died at Liendo Plantation on April 17, 1911. In 1920 his library became the property of Southern Methodist University, and since that time additional data bearing upon his life and philosophy have been added to the collection.