certainty the rottenness and hollowness of all existing knowledge and philosophy, so it was equally easy to devise and practically apply new and natural methods of investigation and construction, which should replace it by knowledge of infallible truth and boundless fruitfulness.  His object—­to gain the key to the interpretation of nature; his method—­to gain it, not by the means common to all previous schools of philosophy, by untested reasonings and imposing and high-sounding generalisations, but by a series and scale of rigorously verified inductions, starting from the lowest facts of experience to discoveries which should prove and realise themselves by leading deductively to practical results—­these, in one form or another, were the theme of his philosophical writings from the earliest sight of them that we gain.

He had disclosed what was in his mind in the letter to Lord Burghley, written when he was thirty-one (1590/91), in which he announced that he had “taken all knowledge for his province,” to “purge it of ’frivolous disputations’ and ‘blind experiments,’ and that whatever happened to him, he meant to be a ‘true pioneer in the mine of truth.’” But the first public step in the opening of his great design was the publication in the autumn of 1605 of the Advancement of Learning, a careful and balanced report on the existing stock and deficiencies of human knowledge.  His endeavours, as he says in the Advancement itself, are “but as an image in a cross-way, that may point out the way, but cannot go it.”  But from this image of his purpose, his thoughts greatly widened as time went on.  The Advancement, in part at least, was probably a hurried work.  It shadowed out, but only shadowed out, the lines of his proposed reform of philosophical thought; it showed his dissatisfaction with much that was held to be sound and complete, and showed the direction of his ideas and hopes.  But it was many years before he took a further step.  Active life intervened.  In 1620, at the height of his prosperity, on the eve of his fall, he published the long meditated Novum Organum, the avowed challenge to the old philosophies, the engine and instrument of thought and discovery which was to put to shame and supersede all others, containing, in part at least, the principles of that new method of the use of experience which was to be the key to the interpretation and command of nature, and, together with the method, an elaborate but incomplete exemplification of its leading processes.  Here were summed up, and stated with the most solemn earnestness, the conclusions to which long study and continual familiarity with the matters in question had led him.  And with the Novum Organum was at length disclosed, though only in outline, the whole of the vast scheme in all its parts, object, method, materials, results, for the “Instauration” of human knowledge, the restoration of powers lost, disused, neglected, latent, but recoverable by honesty, patience, courage, and industry.