The following article (by Meng-hu) is reprinted from Simply Haiku: A Quarterly Journal of Japanese Short Form Poetry, Winter 2011 (http://simplyhaiku.webs.com/meng-huessay.htm). Reprinted with permission. This essay addresses aspects of an aesthetic of solitude in Japanese tradition.
Haiku is distinguished as classical or traditional in its adherence to specific structure, use of seasonal and nature object words, the transition device of "cutting," and juxtaposition. In contrast, modern haiku poets do not promise to use any of these strictures. For structure, the modern haiku poet prefers mere brevity; for seasonal or nature words, they prefer contemporary objects from modern, urban, and technological sources, so-called "keywords;" for cutting and juxtaposition, they prefer free association of words and images.
Beyond adherence to structure, what confirms a haiku as classical is the poet’s expression of relationship to nature -- and, by extension, to existence. In this sense, Basho is the archetypal haiku poet because, as Kenneth Yasuda says, quoting Asaji Nose (1894-1955), Basho
"tried his utmost to master the hidden aspects of nature and to reveal its secrets. What he tried to find was not the outward appearance of nature, but to touch its very heart." 
The modernist argues that this "nature" and this "heart" are themselves interpretations of reality, interpretations not sustained by the modern experience, which necessarily must overthrow traditional ideas in order to clear the way for a new sensibility. This was the argument of Shiki (1867-1902), founder of modern Japanese haiku. Though he modestly proposed only expanding the types of acceptable objects in haiku poetry, his innovation paralleled the modernization trends already sweeping late Meiji culture in Japan.
Modernization in Japan was both a response to Western intervention and an incorporation of its economic and military models, its political and social values. Imitation of a literature developed over centuries in Europe swept Japan within a few decades. Novels proliferated, in successive styles from classical to romantic, from realism to naturalism. Free-verse poetry modernized old genres. The result was a rapid breakdown of all of the characteristics of haiku tradition. The imitation of Western style was not Aristotle's mimesis -- art as a reflection of nature -- but a wholesale expression of a modernized Japan identifying with Western autonomy, nationalism, and power.
As Robert Sayre observed of late 19th-century French symbolists and Parnassians, the concept of art for art's sake ("arte pour l’arte") arises at the terminus of a society's receptivity to social change -- and to art as a catalyst of social change.  It arises with the exhaustion of the expectation that the artist asserts a universal value, a higher order of ethics. Where the poets of France grew disillusioned with the progress of bourgeois society and industrialization, the Japanese intelligentsia embraced it from late Meiji to the militaristic 1940s.
During the post-World War II 1950s, modern American haiku poets (such as the Beats) seemed to respect the binary opposites of culture and thought represented by Japan and the United States, by Judeo-Christianity and Buddhism. But the co-opting of Eastern thought and style paralleled a history of American assault against Japanese culture, here serving an American cultural rebellion in the style of the French poets' "art for art's sake." Under the hegemony of popular American culture, Japan developed gendai (i.e., modern) haiku.
What modern haiku often lacks is precisely what R. H. Blyth described as characteristic of traditional haiku: a way of life, a manner of living. This "way" is the amorphous philosophy and culture of traditional Japan, a rich historical complex. While the historicist will quickly identify ugly social and cultural aspects of traditional Japan, its best poets honed a precise philosophical sentiment, a transcendent "way" independent of the vagaries of institutions and historical eras.
Modern haiku cannot enter a way of living that contradicts contemporary industrial and technological culture. Indeed, the periodic experiments in poetic expression from the early 20th-century imagists to early 21st-century haiku poets often devolve into postmodern ironies as poets attempt to reconcile themselves to the contradictions of modern culture. Nor does modern haiku change the genre's name, thus retaining the plausibility of its genealogy and associative repute.
The roots of traditional haiku are numerous: Buddhism, Taoism, Shinto, Zen, Chinese poetry, folklore, plus the geography, topography, climate, flora and fauna of Japan. These elements form a prerequisite context for haiku -- and a formidable intellectual challenge to the aspiring Western poet. The evolution of Japanese poetic forms such as waka, renga, and senryu, plus the indirect influences of Noh drama, tea ceremony, calligraphy, bonsai, gardens, and ikebana, are part of the historical context of classical haiku. Religious doctrines and cultural practices do not define the mechanics or techniques of haiku but enrich its aesthetics, its spirit.
But haiku theory goes further. As Blyth notes, "Haiku is an ascetic art, an artistic asceticism."  Having discarded technique (i.e., art), modern haiku further separates itself from asceticism. Even the term "asceticism" is viewed askance in the West, for while "askesis" in ancient Greece referred to physical exercise and discipline, it came to be identified with Christian austerities. The term has broader and more refined applications in Eastern thought. By asceticism, Blyth refers to prerequisites of haiku spirit commonly enumerated by many authors: "selflessness, loneliness, grateful acceptance, wordlessness, not-intellectuality, contradiction, humor, freedom, non-morality, simplicity, materiality, love, and courage." 
In ancient Japanese thought, asceticism is a system of reduction, a minimalization -- not as deconstruction but as disengagement, freedom from attachment. Asceticism means a reduction of analysis, reflection, judgment, and dualities. The resulting condition is a sense of solitude, silence, and emptiness. The available potentials are fearlessness, acceptance of what is presented by nature and life, and, ultimately, compassion. All are familiar Buddhist concepts. By incorporating ascetic practices into one's daily life, the creative individual can turn successfully to art, and from art can turn back to asceticism.
The interrelationship of art and asceticism points haiku theory directly towards wabi and sabi. Few discussions, however, explore wabi and sabi -- not even the mid-20th century popularizers Blyth (who touched on them only briefly) and Yasuda, let alone the scholars. With wabi-sabi, however, the notion of a way of life intersects with the poet's way of life (wabi) and the poet’s art, expression, and aesthetics (sabi). 
Wabi is philosophical. Sabi is aesthetic. Wabi is a philosophy of solitude, simplicity, silence, and emptiness. Sabi is the texture and quality of works both found and contrived by human effort. Sabi is an ordering of naturalness and a harmony with nature in form, texture, aging, and color, a simplicity of appearance. Sabi compliments the diurnal activities of the classical poets, their dwellings, their few possessions, the spirit of their lives and poems.
The great practitioners of solitude (wabi) and poetry were the wabizumai, the hermits of classical Japan. No wonder that Japanese poets from Saigyo to Ryokan, and to a great degree Basho himself, were hermits, wanderers, pursuers of an eremitic life intimately grounded in nature. Thus, even in the making of poetry, haiku master Basho deferred to the hermit Saigyo, writing in “Record of a Travel-worn Satchel”:
Dragging my sore feet,
I plod along,
Saigyo expressed the wabi life in his waka. Basho admired Saigyo's practice and spirit, expressing both in his own poetry. The identification of the two poets confirms the continuity of philosophical sentiment and aesthetics that is the basis of classical haiku theory. Their art represents their asceticism, and their asceticism expresses the sense of wabi and sabi. In revisiting the tenets of wabi and sabi, classical haiku theory would further deepen its principles, and further contrast itself to modern theory and its limitations.