by trial and error, empirically, through empirical observation

conceivably, feasibly, hypothetically, possibly, presumably, potentially, easily, probably, actually, even, realistically, mathematically, technically, anyway, logically, maximally, essentially, anyhow, only, effectively, trivially, ordinarily, plausibly, simply, therefore, thus, practicably, infinitely, practically, functionally, perhaps, ultimately, nonzero, somehow, infinitesimally, limitlessly, probabilistically, assuredly, arithmetically, either, legitimately, eventually, conversely, certainly, insurmountably, someday, surely, schrodinger equation, maybe, otherwise, usefully, minimally, nominally, definitively, paradoxically, thermodynamic equilibrium, remotely, ideally, conceptually, moreover, reasonably, not, legally, painlessly, anywhere, readily, scarcely, hardly, vice versa, furthermore, magically, consequently, asymptotically, equivalently, vastly, statistically, necessarily, orbital velocity, boolean algebra, inductively, normally, inherently, substantially, freely, precisely, contrariwise, newtonian mechanics, though, proportionately, inevitably, thermodynamically, ymmv, longer, roughly, axiomatically, stochastically, simultaneously, homologous chromosomes, valence electrons, correspondingly, eminently, electric dipole

absolute zero, abstract, catenary, inerrant, perturb, renewable

in theory, on paper