From about the age of twelve, I entered into another and more advanced stage in my course of instruction; in which the main object was no longer the aids and appliances of thought, but the thoughts themselves. This commenced with Logic, in which I began at once with the _Organon_, and read it to the Analytics inclusive, but profited little by the Posterior Analytics, which belong to a branch of speculation I was not yet ripe for. Contemporaneously with the _Organon_, my father made me read the whole or parts of several of the Latin treatises on the scholastic logic; giving each day to him, in our walks, a minute account of what I had read, and answering his numerous and most searching questions. After this, I went in a similar manner through the _Computatio sive Logica_ of Hobbes, a work of a much higher order of thought than the books of the school logicians, and which he estimated very highly; in my own opinion beyond its merits, great as these are. It was his invariable practice, whatever studies he exacted from me, to make me as far as possible understand and feel the utility of them: and this he deemed peculiarly fitting in the case of the syllogistic logic, the usefulness of which had been impugned by so many writers of authority. I well remember how, and in what particular walk, in the neighbourhood of Bagshot Heath (where we were on a visit to his old friend Mr. Wallace, then one of the Mathematical Professors at Sandhurst) he first attempted by questions to make me think on the subject, and frame some conception of what constituted the utility of the syllogistic logic, and when I had failed in this, to make me understand it by explanations. The explanations did not make the matter at all clear to me at the time; but they were not therefore useless; they remained as a nucleus for my observations and reflections to crystallize upon; the import of his general remarks being interpreted to me, by the particular instances which came under my notice afterwards. My own consciousness and experience ultimately led me to appreciate quite as highly as he did, the value of an early practical familiarity with the school logic. I know of nothing, in my education, to which I think myself more indebted for whatever capacity of thinking I have attained. The first intellectual operation in which I arrived at any proficiency, was dissecting a bad argument, and finding in what part the fallacy lay: and though whatever capacity of this sort I attained, was due to the fact that it was an intellectual exercise in which I was most perseveringly drilled by my father, yet it is also true that the school logic, and the mental habits acquired in studying it, were among the principal instruments of this drilling. I am persuaded that nothing, in modern education, tends so much, when properly used, to form exact thinkers, who attach a precise meaning to words and propositions, and are not imposed on by vague, loose, or ambiguous terms.