MONISM (from Gr. µ6vos, alone)  , the philosophic view of the world which holds that there is but one form of reality, whether that be material or spiritual . The aim of knowledge is explanation, and the dualism or pluralism which acquiesces in recognizing two or more wholly disparate forms of reality has in so far renounced explanation (see DUALISM) . To this extent monism is justified; but it becomes mischievous if it prompts us to ignore important differences in facts as they present them-selves to our intelligence . All forms of monism from Plotinus downwards tend to ignore personal individuality and volition, and merge all finite existence in the featureless unity of the Absolute; this, indeed, is what inspires the passion of the protest against monism . Turning to the historical forms of the theory we may class Plotinus as a mystical monist: he attains to the One which is the All by an act of mystic union raising him above the phenomenal sphere . Spinoza is a materialistic monist with an inconsistent touch of mysticism and a certain concession, more apparent than real, to the spiritual side of experience . Hegel's is an intellectualist monism, explaining matter, sensation, personal individuality and will as forms of thought . The doctrine of Schopenhauer and von Hartmann is a monism of cosmic will which submerges the individual no less completely than Hegelianism, though in a different manner . Haeckel's monism is mere materialism dignified by a higher title . Those who maintain that all these forms of synthesis are hasty and superficial stand by the conviction that the right philosophic attitude is to accept provisionally the main distinctions of common sense, above all the distinction of personal and impersonal; but to press forward to the under-lying unity so far as experience and reflection justify . SeeABSOLUTE; DUALISM; METAPHYSICS; MATERIALISM; IDEALISM .