Recent years have seen a renewed discussion on the notion of monism, or the philosophical view that the world, even though regarded as a plurality of objects, is ultimately one thing. The concept is not new: it is possible to trace its historical background from the times of the presocratics. However, it is not easily accepted, for it looks quite counter-intuitive to deny fundamental reality to the objects we perceive. Still, contemporary philosophers of science such as Schaffer, Esfeld and Gribbin argued for some kind of oneness or holistic cosmos not only as the corollary of the study of traditional metaphysical tenets, but as the natural result of a close look at quantum mechanics, for instance. Whether this holism accounts for the rejection of any pluralistic theory is debatable; however, its solely coherent existence supposes a problem for the atomist. In this talk I’ll argue that this old conception cannot be, at least, discarded, for it still poses challenging questions related to metaphysics and science. After doing a brief introduction on the historical background of the concept of monism in relevant figures such as Parmenides, Spinoza and Bradley, I will discuss some contemporary approaches, evaluating both their strengths and weaknesses. Finally, I’ll give my own perspective, arguing for a kind of monism based on not just the lack of basic properties of particulars and the necessity of a fundamental background, but on the notions of “presentation” and “immediacy”. These notions are not used by the aforementioned authors (although Bradley would talk of “Immediate experience”) but I think they have a connection to concepts such as “pure act” in Giovanni Gentile and “will” in Schopenhauer. I intend to demonstrate that rather than being mere epistemological categories they make explicit a particular character of reality we are not used to accepting.