What is monism? Explain its features

The metaphysical position which reduces the whole reality into one ultimate substance is called monism. Monism is the Greek word signifying that which is alone or single. There are three positions of monism: Materialism, Idealism and Neutralism. If one believes that that single ultimate reality is materialistic in nature, that position is known as Materialistic Monism. The position that the single absolute reality is spiritual in nature is termed Spiritualistic monism or Spiritualism. This is an idealist view because the spiritual part of reality is beyond the material part. Neutralism holds that reality is neither mind nor matter but a neutral stuff of which mind and matter are but appearances or aspects.

 Materialism had its advocates among the early Greek philosophers like Thales. Democritus and Lucretius also conceived that the world was reducible to material elements. The doctrine of materialism asserts that that there is finally one reality, matter. In the Indian tradition, the Carvaka School had advocated materialism. They rejected the very existence of all spiritual entities and emphasized that reality is constituted by four material elements namely water, fire, air and earth. Idealism, too asserts that reality is one but that one ultimate substance is mind or spirit. For the idealist, matter is at best a representation or manifeststion of mind. Accordingly, mind is real and matter is just an appearance. 

In modern times, George Berkeley advocated Subjective idealism and Hegel’s position is known as Absolute Idealism. Spinoza is the well-known representative of neutral monism. For Spinoza, there is one single reality which he called substance, and that ultimate substance is God. He called God as Natura naturans, which means ultimate substance. The world and its various appearances are the attributes and modes of the ultimate substance - Natura naturata.