It may be difficult for the British mind, familiarized from infancy with the philosophy of common sense, to grasp the idea which this doctrine involves; but, on the principles of absolute Idealism, it may be easily explained, and may even seem to have some foundation in facts that must be acknowledged by all. There are _two_ cases, particularly, which may serve to illustrate, if they cannot suffice to prove, it. The first is that of the Supreme Intelligence, conceived as existing before the production of a created universe, when He was himself the sole "subject" and the sole "object" of thought; in other words, the absolute "Subject-Object." The second is that of the human consciousness, conceived as occupied solely with certain subjective mental states, when the mind may be said to be at once the "subject" and the "object" of its own thought. There are cases, then, in which mind may be regarded as a "subject-object;" the case of human consciousness, when the mind takes cognizance of its own states or acts, and the case of the Divine consciousness, while as yet the created universe had not been called into being. But the question is, whether, _in all cases_, the "subject" and "object" of thought are the same? or, whether existence and thought are _universally_ identical? An affirmative answer to this question would imply, that nothing whatever exists except only in the mind that perceives it; that, according to Bishop Berkeley, "the existence of unthinking things without any relation to their being perceived" is an absurd or impossible supposition; that "their _esse_ is _percipi_," that is, that their being consists in their being perceived or known; whence it would follow, as Berkeley himself admits, that we have no reason to believe in the continued existence of the desk at which we write, after we have left the room in which we see it, excepting such as may arise from the supposition, that if we returned to that room we might still see it, or that in our absence it may still be perceived by some other mind. Existence is identified with thought, and nothing exists save only as it is thought of. Why? Simply because it can become known to us only through the medium of consciousness, and that, too, in no other character than as _a phenomenon of our own minds_.