Morgan, Conwy Lloyd (1852–1936), comparative psychologist and philosopher, was born in London on 6 February 1852, the second son of James Arthur Morgan, solicitor, and his wife, Mary Anderson. He received his early education at Brenchley, Kent, and at the Royal Grammar School, Guildford, his parents having moved to Weybridge a few years after his birth. The focus at the latter school was mainly on classics, with some mathematics but no science. Lloyd Morgan was, however, early attracted to scientific studies, and his father had concerns in several mining companies. Consequently, at the age of seventeen, he entered the School of Mines in London, where he was duke of Cornwall scholar, with the intention of becoming a mining engineer. Although he excelled in his studies, achieving both the Murchison and the de la Beche medals, he became increasingly interested in the pursuit of pure science. On obtaining his diploma as associate in mining and metallurgy, he accepted a post as private tutor to a wealthy Chicago family which gave him the opportunity of extensive travel in North and South America. On his return he resumed his scientific studies at the Royal College of Science, where he worked, among other teachers, under T. H. Huxley, whose influence upon him was profound.

During this later period as a student Lloyd Morgan acted as an assayer for a mining company in Cornwall. In addition he was a lecturer at Weybridge School and, later, visiting master at Chatham School, Ramsgate. But his first regular professional post was in South Africa at the Diocesan College at Rondebosch, where he was appointed in 1878 to teach not only the physical sciences in general, but also English literature and, for a time, constitutional history. On 12 June of the same year he married Emily Charlotte Maddock (b. 1850/51), daughter of the Revd Henry William Maddock, vicar of All Saints, St John's Wood, London. They had two sons, the elder of whom predeceased Lloyd Morgan.

In 1884 Lloyd Morgan returned to England to succeed W. J. Sollas in the chair of geology and zoology at University College, Bristol, where he was destined to pass the rest of his professional career. Three years later he was elected principal of the college, a post which in the early days of the university colleges was regarded as compatible with the continued tenure of a chair. But as the college developed the administrative work grew with it, and when in 1910 the university charter was granted Lloyd Morgan accepted the vice-chancellorship of the new university only in order to give it a start. After a tenure of about three months he resigned and resumed the work of his chair, by then renamed the chair of psychology and ethics, from which he retired in 1919. He lived on in Clifton until 1926, and even on one or two occasions returned to the university to give temporary assistance in the department of philosophy, as it had by then become.

As principal Lloyd Morgan's impressive appearance, his upright and kindly personality, and his intellectual eminence commanded universal respect and liking, particularly among those most closely associated with him, but he had little taste for administration and was not particularly well equipped to handle some of the more assertive academic politicians of the time. On the other hand there can be no reservations about the value of his services to learning. A self-proclaimed sufferer from ‘cacoethes scribendi’, he was an exceptionally prolific author. Between 1876 and 1934, only one year (1918) passed without a publication from Lloyd Morgan. Following his Water and its Teachings (1882) and Facts around Us (1884) with approximately a dozen papers on Palaeozoic rocks of the Bristol area, his main interest in the early days of his tenure of the chair at Bristol was on the side of geology. But that soon gave place to what for many years occupied the centre of his attention, the study of animal and comparative psychology. As literary executor to George J. Romanes, Lloyd Morgan assumed the reputation of one of the foremost researchers in the field of mental evolution. Indeed, it would not be too much to say that, in the English-speaking world at any rate, he was one of the chief founders of the scientific study of animal psychology. He was among the first to apply systematically the methods of experiment to the subject. The results of his investigations appeared in a long series of publications of which the most important are Animal Life and Intelligence (1890–91), Habit and Instinct (1896), Animal Behaviour (1900), and Instinct and Experience (1912).

Lloyd Morgan is perhaps best known for his statement about assessing the relative roles of instinct, intelligence, and reason in the experimental study of animal behaviour. First presented at the International Congress of Experimental Psychology, held in London in 1892, and subsequently published in his An Introduction to Comparative Psychology (1894), this later became known as Lloyd Morgan's canon. Stating that in no case is 'an animal activity to be interpreted as the outcome of the exercise of a higher psychical faculty, if it can be fairly interpreted as the outcome of one which stands lower on the psychological scale', the canon was designed to bring scientific rigour and evolutionary continuity to the anthropomorphic psychological approach to animals. Arguably its misinterpretation had a profound impact on the development of behaviourism.

With J. M. Baldwin, H. F. Osborn, and E. B. Poulton, Lloyd Morgan arrived independently at the theory of organic selection, or the Baldwin effect, in the early 1890s. This theory explained apparently Lamarckian evolution in neo-Darwinian terms. According to this theory an organism exposed to a new environment might initially survive through adaptation borne of learned habits. Among these successful organisms spontaneously generated hereditary adaptations that are identical to the previously learned habits might arise. Although generated through the random action of natural selection, successful behavioural attributes may, therefore, appear to be the result of use inheritance.

Influenced by the writings of George Berkeley from an early age Lloyd Morgan grappled with the problem of mind–body dualism. His proposed solution was shaped by his combined interests in metaphysics and experimental evolutionary psychology. Committed to a monism of ‘mind stuff’ throughout most of his active career in comparative psychology, Lloyd Morgan accorded mentality a positive role in evolution. In his later years, however, his interest turned more exclusively to the metaphysical underpinnings of his monism. In this field he developed and gave his own interpretation to the idea of the emergence of novelty which was being discussed by Samuel Alexander and others at that period. His most important works in this field of investigation are his two courses of Gifford lectures delivered at St Andrews University in 1922 and 1923 and published as Emergent Evolution (1923) and Life, Mind and Spirit (1926). Although he rejected religious orthodoxy he detected a divine plan at work in emergent evolution, which denied materialist reductionism in evolutionary explanations of the natural world. In short, evolution generated novel products that could not be explained strictly on the basis of component elements or causes. Undoubtedly his explications of emergent evolution contributed to his election as president of the Aristotelian Society in 1926.

Lloyd Morgan's pre-eminence in his chosen field was rewarded with numerous honours. He was elected FRS in 1899, being the first fellow to be elected for psychological work, and he was elected first president of the psychological section of the British Association for the Advancement of Science in 1921. He received honorary degrees from the University of Aberdeen (1903), the University of Wisconsin, Madison (1904), and Bristol University (1910). On two occasions (1895/6, 1904), he was selected to deliver a course of Lowell lectures at Harvard.

Throughout his life Lloyd Morgan seemed intent on being the living embodiment of his emergent monism. In Mind at the Crossways (1929) he argued that art and science represented emergent attitudes towards beauty and truth respectively. Both the contemplative and the emotional constituted the emergent level. Determined to balance his science with art, Lloyd Morgan was an integral part of the various facets of Bristol community life: he was president of the Bristol Cambrian Society; vice-president of the British Empire Shakespeare Society; member of the committee controlling Leigh Woods; and president of the Clifton High School for Girls. He was also an active participant in university extension work in Bristol and the surrounding region. Contemporaries remembered him as 'tall and spare of figure, with humorous eyes' (The Times, 9 March 1936, 8a). 'In the town he was a familiar and respected figure, who could be seen every day cycling to work, to golf, or to Church, with no overcoat in any weather, and his long beard resting on the handlebars, or blowing wildly over his shoulder' (Grindley, 1). In 1926 Lloyd Morgan finally retired to Hastings, where he died at his home, 23 Elphinstone Road, on 6 March 1936. He was buried at the borough cemetery, Hastings.