. What schools of Western art emerged in the first half of the 20th century, and what were their artistic ideas?

Early 20th Century to World War I: Fauvism, Expressionism, Cubism, Futurism, and Abstraction

The world recognizes Cézanne, Van Gogh, and Gauguin as the grandmasters of 20th-century modern art, but their influence was limited while they were still alive, and it was only in Paris, France, that the first large-scale public exhibitions of their works were held in the period from 1901 to 1906. The painters who inherited their ideas and spread them to the 20th century were a small faction of artists, the Nabis. The main representatives were Célusier, P. Bonnard, M. Denis, E. Vial and others.

The Fauvist paintings born in France in 1905, represented by Matisse, used bright and heavy colors, and created strong picture effects with straightforward and rough brushwork, fully displaying the expressionist tendency of pursuing emotional expression. Representatives include Matisse, Flamenck and Derain. In Northern Europe, with the successive establishment of the German Bridge Society in 1905 and the Blue Knights Society in 1909, Expressionism ascended to the painting world as an important school. It was represented by Edvard Munch, Ensor, Schiele, Koksika, and Nolde, as well as Kirchner of the Bridge School and Kandinsky and Marck of the Blue Knights. Fauvism and Expressionism are similar in their aesthetic goals and artistic pursuits, and both are very bold in their use of color, but the purpose of using color is different. Fauvism was about aesthetics, while Expressionism was about using color and wild lines to express feelings and ego, and to give vent to inner bitterness.

Cézanne, the representative of Post-Impressionism, was the first painter who brought figuration into abstract form, and his understanding of "reducing nature to three basic shapes, namely, cylinder, cone and sphere" gave rise to the birth of Cubism, and the Cubist paintings of Braque and Picasso, which rose to prominence in 1908, inherited Cézanne's law of figuration, breaking down natural objects into three basic shapes. In 1908, the rise of cubist paintings represented by Braque and Picasso inherited Cézanne's law of shape-making and decomposed natural objects into geometrical blocks and surfaces, so as to fundamentally break away from the visual law and spatial concept of traditional paintings. However, in Picasso's opinion, there was no such thing as "abstract" art, which was only a matter of some people emphasizing on style, and some emphasizing on life. After the emergence of Cubism, in the 1920s of the last century, there also appeared Futurism, Constructivism, Absolutism, Neo-Stylism and other branches of Cubism, among which the Futurism art movement appeared in Italy in 1909, which made use of Cubism's method of decomposition of the objects, and added the factors of expressing speed, time and power, in order to embody the "beauty of speed". "The representative figures are Boccioni, Balla, Severini and so on.

Cubism and Fauvism promoted the independent development of form and color respectively. And Kandinsky, the leader of the Blue Knights, discovered its wonders, i.e., the use of color and shape alone can convey the artist's feelings and emotions, from which he leaped into the category of abstractionism. His abstract painting "Untitled", created in 1910, is regarded as the first purely abstract work ever produced by mankind, which in turn changed the art of the 20th century and became the most resilient art in the past 100 years. Another representative of the abstract school was the Dutch painter Piet Mondrian, and the two represented the two directions of lyrical abstraction and geometric abstraction respectively.

World War I to the end of World War II: Dadaism, Surrealism, Social Realism, and Socialist Realism

World War I gave rise to the Dadaist school of thought, in which artists were not only opposed to war, authority, and tradition, but also anti-aesthetic and anti-art. Duchamp's paintings of Da Vinci's Mona Lisa with a beard and urinals as works of art were labeled "anarchist" and hated by society. However, Duchamp's concepts of "art is everywhere" and "everything is art and everyone is an artist", expressed in his finished works, set an example for future generations of defying authority, transcending limitations, and pursuing complete freedom, and have taken root in the field of modern American art. Other representative painters include René Magritte, Max Ernst and Grosz.

As the high tide of the Dadaist movement subsided, many Dadaists turned to Surrealism. Based on the theories of Bergson's intuitionism, Freud's psychoanalysis, and dream psychology, this school of painters sought to show the unconscious and subconscious world. Their paintings often combined specific detailed depictions with fictionalized moods to represent dream and hallucinatory scenes. Representative painters include Dalí, Juan Miro, Chagall, Ernst, René Magritte, and others.

In 1922, with Rivera, Orozco and Siqueiros as the representative of the Mexican muralism movement, announced the severance of the relationship with all the aristocratic art, to create a new art with a social purpose, monumental forms of expression, this trend swept through the Americas to form the social realism school of painting, and reached its peak during the Great Depression. Similarly, the former Soviet Union inherited the 19th century style of critical realism, and the socialist realism that emerged in the 1930s was also an art that reflected social reality and served politics, and formed a system of its own, which had a great impact on the socialist countries and modern China. This is also the contribution of the Russian nation to mankind in both figurative and abstract (Kandinsky, the founder of abstraction) fields of painting. The representative painters of Socialist Realism are Alexander Deineka, Alexander Gerassimov and Isaak Brodsky.

Post-World War II: Abstract Expressionism, Pop Art, and Hyper-Realism

At The Armory Show in 1913 and the European artists who immigrated to the United States after World War I introduced modern art to the United States. After the end of World War II, the United States gradually replaced Paris as the center of the emerging art movement. Abstract Expressionist painting, represented by Pollock and de Kooning, synthesized the characteristics of Abstraction and Expressionism, focusing on form while highlighting emotion and color. On this basis, Pollock abandoned the traditional painting tools and pioneered the action painting "drip sprinkle method" (similar to splashing ink, he is also the second Western master with Chinese elements in his paintings, the other being Klimt), and this kind of free-spirited, amorphous abstract painting style is regarded as the beginning of the era of abstract art in the United States, which is free from European influences, and has become a symbol of opposition to the constraints, and the beginning of a new generation. It became the embodiment of the American spirit that opposes bondage and advocates freedom, and is in the same lineage with the concept of Duchamp, the representative of Dadaism.

Pop art (also known as neo-realism and neo-Dadaism), which emerged in Britain in the early 1950s and flourished in the United States in the mid-1950s, inherited the spirit of Dadaism, and utilized a lot of wastes, merchandise posters, movie advertisements, and pictures from various newspapers and magazines to make collage combinations. It can be directly based on real-life objects, and the objects in life can also be directly used as Pop Art works. According to Lichtenstein, "to use the subject matter of commercial art for painting is Pop Art". In the eyes of Pop artists, "art is life and life is art", which are exactly the concepts advocated by Duchamp. The name Pop originated from Hamilton's "What Makes Today's Families So Cozy and Different? The most influential painter was Andy Warhol, the initiator and main advocate of the American Pop Art movement. Pop art was followed by new and popular art such as minimalism, light effects, and hard-edge painting.

The rise of photorealism in the early 60s and 70s, that is, the use of photographic results for objective reproduction and realistic depiction, meant that abstract painting gradually completed the metamorphosis of rational identity and began to enter a period of artistic silence. Building on this, hyperrealism used photographs as a reference to create works with more explicit and detailed renderings. They are distinguished from traditional realism by the absence of subjective feelings, the use of the same eye (the camera) to observe and reflect, and the extraordinary aesthetic and psychological effect of enlarging the dimensions of everyday things, whereas realism is infused with the subjective passions of the author and is a subjective realism or humanistic reality. The representative painters of photorealism and hyperrealism, Ralph Goings and Chuck Close, the Italian painter Ventrone, the Chinese painter Luo Zhongli's Father and Chen Yifei's The Flutist, may have the shadow of photorealism, while the oil paintings of Weng Wei and Li Guijun have the obvious traces of digital photos, and the brush painter Luo Hanlei's Kitten is a reproduction of her own painting, while the brush artist Luo Hanlei's Cat is a reproduction of her own painting. Kitten" by Luo Hanlei, a brush painter, is a photo of her daughter.

Besides the above, there are also ephemeral art, earth art, new media art, video art, and large-scale installations that can be categorized as modern art, many of which are beyond the scope of fine art.