Nonduality is a central concept in certain spiritual and philosophical traditions, mainly in the East, which affirms the fundamental unity of reality beyond appearances of duality and separation.
This means that, despite the diversity and multiplicity of forms that we perceive in the world, there exists an underlying unity that transcends these apparent distinctions. This concept is often explored in traditions such as Advaita Vedanta (in India), Buddhism (notably Mahayana and Zen), as well as in certain forms of Taoism.

In Advaita Vedanta, for example, non-duality (or Advaita, meaning "non-two") refers to the idea that Atman (the individual self) and Brahman (the ultimate cosmic reality) are one. one and the same thing. Distinctions between the individual self and the external world, or between being and the divine, are considered illusions (Maya) created by the human mind.

In the West, certain philosophical currents, notably those influenced by mysticism or transcendentalist philosophies, have addressed ideas similar to non-duality. Thinkers such as Plotinus in Neoplatonic philosophy or Christian mystics like Meister Eckhart explored ideas of unity beyond the usual distinctions of the phenomenal world.

Thus, non-duality invites us to go beyond dualistic perception (good/evil, subject/object, transcendence/immanence) to recognize a reality where everything is interconnected and not separated. Meditative and contemplative practices are often recommended in these traditions to access such direct understanding of non-duality.