See C. Bell's Old Friends (1956); biography of Vanessa Bell by F. Spalding (1983); R. Marler, ed., Selected Letters of Vanessa Bell (1993).
By World War I their marriage was over. Vanessa had begun a lifelong relationship with Duncan Grant and Clive had a number of liaisons with other women such as Mary Hutchinson. However, Clive and Vanessa never officially separated or divorced. Not only did they keep visiting each other regularly, they also sometimes spent holidays together and paid "family" visits to Clive's parents. Clive lived in London but often spent long stretches of time at the idyllic farmhouse of Charleston, where Vanessa lived with Duncan and their three children, that is, her children by Clive and Duncan. He fully supported her wish to have a child by Duncan and allowed this daughter to bear his last name.
Vanessa's daughter by Duncan, Angelica Garnett, was raised as Clive's daughter until she married. She was informed, by her mother Vanessa, just prior to her marriage and shortly after her brother Julian's death that in fact Duncan Grant was her biological father. This deception forms the central message of her memoir, Deceived with Kindness.
Bell was one of the most prominent proponents of formalism in aesthetics. In general formalism (which can be traced back at least to Kant) is the view that it is an object's formal properties which makes something art, or which defines aesthetic experiences. Bell proposed a very strong version of formalism: he claimed that nothing else about an object is in any way relevant to assessing whether it is a work of art, or aesthetically valuable. What a painting represents, for example, is completely irrelevant to evaluating it aesthetically. Consequently, he believed that knowledge of the historical context of a painting, or the intention of the painter is unnecessary for the appreciation of visual art. He wrote: "to appreciate a work of art we need bring with us nothing from life, no knowledge of its ideas and affairs, no familiarity with its emotions"(Bell p27).
Formalist theories differ according to how the notion of 'form' is understood. For Kant, it meant roughly the shape of an object - colour was not an element in the form of an object. For Bell, by contrast, "the distinction between form and colour is an unreal one; you cannot conceive of a colourless space; neither can you conceive a formless relation of colours"(Bell p19). Bell famously coined the term 'significant form' to describe the distinctive type of "combination of lines and colours" which makes an object a work of art.
Bell was also a key proponent of the claim that the value of art lies in its ability to produce a distinctive aesthetic experience in the viewer. Bell called this experience "aesthetic emotion". He defined it as that experience which is aroused by significant form. He also suggested that the reason we experience aesthetic emotion in response to the significant form of a work of art was that we perceive that form as an expression of an experience the artist has. The artist's experience in turn, he suggested, was the experience of seeing ordinary objects in the world as pure form: the experience one has when one sees something not as a means to something else, but as an end in itself (Bell p45).
Bell believed that ultimately the value of anything whatever lies only in its being a means to "good states of mind" (Bell p83). Since he also believed that "there is no state of mind more excellent or more intense than the state of aesthetic contemplation"(Bell p83) he believed that works of visual art were among the most valuable things there could be. Like many in the Bloomsbury group, Bell was heavily influenced in his account of value by the philosopher G.E. Moore.