Berkeleyan substantialism combines the characteristic features of the other theories, and affords an easy solution of many difficult problems in philosophy. It has in common with idealism--whence it is sometimes, but erroneously, called by that name--that it regards all _material_ bodies and things as facts or items of consciousness. It agrees with materialism that a substance is essential to consciousness, and that the consciousness of man serves the needs of his body, though that is not the highest use to which it can be put. It confirms the metaphysical view that intelligence is not, in its abstract or essential character, dependent on the body, and may therefore survive the body. This is the theory on which the following logic is based: I shall refer to it briefly as Substantialism. II--ONTOLOGICAL NOTIONS Substantialism has two main divisions--Ontology, which treats of the mental substance in itself, and Logic or Metaphysic, which deals with its consciousness. The present essay is specially concerned with logic, but certain ontological premises must be assumed to render the logic intelligible. This follows from the subordinate relation of consciousness to substance. The substantial mind consists of two principal parts--a SELF and a PLASMA--the Atman and Aka['s]a of Sanscrit philosophers. Self is the seat of Energy and Consciousness. The plasma is inert and unconscious; it protects the Self and receives, communicates, and retains impressions of experience, both the external and the internal[1]. The Self would be conscious though isolated from other minds, at least from those of its own grade of being. It would feel the fluctuations of its energy. But the experience called 'external' depends on the mutual action of minds. It is the form into which their consciousness is thrown when they come in contact. It lasts no longer than the contact, and so has only a casual existence. The constitution of the mind is not given by Berkeley, and on other points also we must supplement and correct his philosophy. He was wrong as regards the mental cause of the perception of the Inorganic or Dead. Since external experience implies that another mind is operating upon ours, what mind is operating when we perceive an object that is apparently mindless? Berkeley replies that it is the supreme mind that is then acting upon us. Many objections can be urged against this view. I will mention only one, which seems to me conclusive. By every canon of judgment we possess, the living or organised is better--more important and significant--than the lifeless and elemental; so if Berkeley's reasoning be valid the phenomena excited by finite and created beings are superior to those excited by their Creator. The movements of a living man are referred to a human mind--a putrescent carcase is a vision immediately induced by the Deity.