The phrase ‘everything is one’ is something of a meme, whether taken seriously by spiritual practitioners, propounded by new-agers or spoofed in The Onion. But could the phrase have originated from profound mystical insight into the nature of reality, and thereby be worthy of serious philosophical investigation? And if so, can we get a better handle on what it could mean to say, in all seriousness, that everything is one? One what? This is the topic of my paper. I won’t be arguing for the ambitious thesis that everything is one, but rather undertaking the more modest task of trying to understand how reality might be configured if what the mystics are saying is correct. First, there seems to be a disguised claim about grounding: ‘the one’ is that which grounds all being. Second, it is said that what grounds and unifies all being is a mode of consciousness, into whose essence mystics are claimed to have had direct insight. My paper will attempt to sketch a preliminary answer to the following questions. What kind of consciousness could meaningfully be called ‘consciousness’ and yet conceivably be apt to ground what we take to be the familiar spatio-temporal world of tables, chairs, people, cats, atoms etc? And how might these objects be grounded in such consciousness?