A philosophic article, entitled _Berkeley and Idealism_, and published in June of 1842, was designed to meet the attack of Mr. Samuel Bailey, who had written a _Review of Berkeley's Theory of Vision_, criticising the soundness of his views. Mr. Bailey replied, and Ferrier a year later published an article on that reply. Ferrier rightly appreciates the very important place which ought to be allowed to Berkeley as a factor in the development of philosophic truth--a place which has only been properly understood in later years. He saw the part he had played in bringing the real significance of Absolute Idealism into view, and deprecated the representation of his system made by David Hume, or the popular idea that Berkeley denied all reality to matter. What he did deny was the reality which is supposed to lie beyond experience, and his criticism in this regard was invaluable as a basis for a future system. In his own words, he did not wish to change things into ideas, but _ideas_ into _things_: matter could not exist independently of mind. But yet Ferrier is perfectly aware that Berkeley did not entirely grasp the absolute standpoint that the thing is the appearance, and the appearance is the thing. Regarded merely as a literary production, this article is entitled to rank with the classics of philosophic writings both as regards the beauty of its style and its logical development. Ferrier does not often touch directly on questions of religion or theology, but there is an interesting passage in this essay which shows his views regarding the question of immortality. He is talking of the impossibility of our ever conceiving to ourselves the idea of our annihilation. Such an idea could not be rationally articulated. We _appear_, indeed, to be able to realise it, but we only _think_ we think it: real thought of death in this sense would involve our being already dead; but in thought we are and must be immortal. 'We have nothing to wait for; eternity is even now within us, and time, with all its vexing troubles, is no more.'