Boscovich, in his treatise De continuitate lege (1754) applied the Aristotelian distinction between potentia and actus to his conception of space: the “potential” geometrical space is continuous and infinite, while the “actual” physical space is discrete, i.e., it is constituted of “points-atoms” which are bearers of a single force in nature that should be described by the universal natural law(s). In this way Boscovich tried to overcome the traditional opposites between empty space and physical objects, and also the principal philosophical controversy between idealistic and materialistic theories of nature. This distinction between potentiality and actuality was further developed in Boscovich’s main work Theoria Philosophiae Naturalis (1758) where it served him to upgrade Newton’s conception of forces into a unified “dynamic” theory of nature. In my contribution, the main point is that Boscovich’s distinction between potential and actual space might be relevant and inspiring in modern search for unification of nature – i.e., not just for the unification of four basic physical forces in the so-called “Final Theory”, but for the union of nature and mind, especially from the standpoint of modern cosmology. Next to the treatise De continuitate lege, my starting point is Boscovich’s Appendix to Theoria Philosophiae Naturalis, titled “Ad metaphysicam pertinens: De Anima & De Deo”) – however, my contribution is not principally historical. My plan is the following: (1) first I shift and generalize Boscovich’s distinction between potentia and actus from the classical geometrical space to the “phase space” of possibilities (we may call it also Hilbert space); (2) theoretical possibilities in the contemporary quantum physics and/or in cosmology can be conceived as different universes in a multiverse, in some “phase space”; (3) now, the principal question is the following: how the actualization (the “choice”) in a huge space of possibilities happens (in cosmology, this is called the problem of “fine tuning”), especially whether mind has some role in this actualization; and finally (4): how Boscovich’s conception of the “potential space”, which he considers also as the “space of soul” (and/or of mind/spirit) vs. the “actual space” of physical point-particles, could be helpful for solving the modern “mind–body problem”, not only in cognitive science, but also in cosmology, i.e., for solving the enigma of the putative “fine tuning” of our universe, which is actually – among and in spite of the huge number of theoretical possibilities for the values of the free physical parameters – “just fit for life”. I think that Boscovich’s ideas about soul and God in relation to nature might indeed be helpful in this great, perennial philosophical search, as well as in the contemporary scientific research.