Scruton's argument is that modern art has completely lost its way. It is self-centred and never looks beyond the basic biological animal existence of mankind, often having a puerile obsession with excretory functions.
Mechanistic modern architecture is similarly anti-human. It attempts to reduce people to mere components of ugly utilitarian machines.
Scruton believes that all great art has a 'spiritual' dimension, even if it is not overtly religious. It is this transcendence of the mundane that we recognise as 'beauty'.
A path out of the spiritual desert.
In Buddhist terminology we would say that true art, even when it reflects samsara (the realms of chaos, addiction, squalor and suffering), shows that there is a path out, and often acts as signposts along the path. However most of modern art merely reflects, and often wallows in squalor, without acknowledging any possibility that there may be other states of existence. It has turned its back on beauty and wanders aimlessly in a spiritual desert.
Tantra and art
We could go further and say that great art is a 'tantric' practice in its widest sense, where tantra is the mental transformation of the ordinary environment to the environment of a spiritual being. Scruton emphasised this aspect in the transformation of lust (attachment) into Platonic love, where the energy of carnal desire is channelled into spiritual objectives.
Modern architecture reflects a materialistic philosophy which generates an environment fit only to be inhabited by automata, and is thus an expression of the philosophical doctrine of materialism , which rejects any possibility of a spiritual dimension of existence.
Brutalist Architecture - Demoralising and dehumanising to live in.
Modern art engages the mind on a purely superficial level by its constant attempts at 'originality', which usually end up as scatological attempts to 'shock' some imaginary strawman of middle class public opinion ('Épater la bourgeoisie').
But this public opinion has actually long since become jaded by the antics of the self-appointed avant-garde, which may have been shocking the first time round, but have become boring and vacuous with repetition.
Procedural and Mechanistic Cult of Ugliness
Scruton also attacked conceptual art and the cult of ugliness. Sculptor Alexander Stoddart claimed that conceptual art is word-bound and exhausted in its verbal description. After you have had the idea of putting half a cow in a tank of formaldehyde, the object itself can be dumped as irrelevant.
Conceptual art is mechanistic and procedural:
The concept(s) or idea(s) involved in the work take precedence over traditional aesthetic and material concerns. Many of the works, sometimes called installations, of the artist Sol LeWitt may be constructed by anyone simply by following a set of written instructions. This method was fundamental to LeWitt's definition of Conceptual art, one of the first to appear in print:
“In conceptual art the idea or concept is the most important aspect of the work. When an artist uses a conceptual form of art, it means that all of the planning and decisions are made beforehand and the execution is a perfunctory affair. The idea becomes a machine that makes the art." - http://en.wikipedia.org/wiki/Conceptual_art
In contrast, real art engages the deeper levels of the mind by invoking qualia - qualitative experiences of beauty that are non-material and go beyond mere mechanistic proceduralism.
- Sean Robsville
Buddhism versus Materialism
Numinous Symbolism - Pagan, Buddhist and Christian
Chesterton on Mysticism
Reductionism and Buddhist Philosophy
Consciousness and mind are not emergent phenomena or emergent properties of matter
Qualia - Objective versus Subjective Experience