'Having coasted past the ancient arts' in the first part of The Great Instauration, Bacon proceeded to his second point, 'to equip the intellect for passing beyond'. This task involved teaching men how to make 'better and more perfect use of human reason in the inquisition of things' and how to take advantage of 'the true helps of the understanding'. By such means the intellect could be 'raised and exalted and made capable of overcoming the difficulties and obscurities of nature'. Bacon attempted to fulfil these aims in his greatest philosophical work, The New Organon, or Directions concerning the Interpretation of Nature, which he wrote in Latin and revised twelve times before its publication in 1620. It was intended to replace Aristotle's Organon and to provide a new art of logic which would differ from Aristotle's 'in the end aimed at, in the order of demonstration, and in the starting point of the inquiry'. What the intellect needs, according to Bacon, is not the scholastic method of syllogisms, which only enables a man to win arguments, but a means to
'command nature in action', a form of induction which 'shall analyse experience and take it to pieces, and by due process of exclusion and rejection lead it to an inevitable conclusion .'
The reasoning used to 'prove' that the heavenly bodies are composed of a fifth essence, an element different from the four sublunary elements of earth, air, fire, and water, exemplifies what Bacon opposed:
The heavenly bodies move eternally in circles. But it is the nature of earth and water to move down, and of air and fire to move up. Therefore the eternally circling heavenly bodies are not composed of earth, air, fire, and water, but of a fifth essence.
Such reasoning is valid if the first two propositions are true; Bacon objected that all too often they were assumptions based not on facts but on authority, tradition, novelty, prejudice, false reasoning, faulty observation, or inadequate evidence. He also objected that if the propositions were true they included the final statement and therefore merely clarified knowledge by bringing it into the open.
In his earliest works Bacon went to extremes in trying to avoid such unrealistic assumptions. He would draw up tables of facts and would narrow them by excluding what was not relevant. For example, in collecting facts about heat, he would learn that both dense and tenuous things could be hot; thus both denseness and tenuousness could be excluded from the possible forms of heat. In time, by means of such exclusions, he would arrive at an understanding of the real nature of heat.
In practice Bacon seems to have realized that tabulating and excluding were insufficient, for he began to advocate that researchers should sort out 'prerogative instances', facts which would be especially useful for gaining information or for indicating how to proceed. In other words, 'prerogative instances' would conduce to hypotheses — hypotheses which would then be tested by experiments. Bacon used to be called the father of experimental science, but his claim to this title was denied because his method of tables and exclusions is not the procedure of modern science whereby an experimenter somehow formulates a guess, tentative theory, or hypothesis and then tests it in experiments. However, if one reads between the lines and interprets Bacon with common sense, it is clear that he realized the impossibility of reaching final truth by means of tables and exclusions or from the 'axioms' or hypotheses which emerged from them. Hypothesizing inevitably was involved in the classifying, in the selection of prerogative instances, and in the formulation of the 'axioms'. Scientific truths would emerge when these were tested by systematic experiments.
Bacon's final method for research is given at the end of New Atlantis: first, all available information is gathered about experiments; to this is added what is discovered by men who 'try new experiments such as themselves think good'. The resulting information is then compiled and tabulated. Next, based on these collections and discussions about them, there are 'new experiments of a higher light, more penetrating into nature than the former'; and finally these latest discoveries by experiments are formulated 'into greater observations, axioms, and aphorisms'. Although Bacon did not clearly or fully state the method of hypothesis and verifications, it was implicit in such a system.
Certainly the experiment which caused his death, the stuffing of a chicken with snow to see if it would retard the spoiling, exemplifies the method of testing hypotheses by experiment.
The third part of the Great Instauration, a compendium of natural science entitled The Phenomena of the World, or Natural and Experimental History for the Foundation of Philosophy or Science, was only partially fulfilled by Sylva Sylvarum, a largely derivative compilation of a thousand statements about science and related subjects. The latter included information about witches, keeping oranges fresh, silencers for guns, the diseases of corn, the possibility of what is now called extra-sensory perception, and the significance of dreams. Bacon also planned to write six 'histories' for this third part of the Instauration and completed The History of Winds, The History of Life and Death, and part of The History of Rarety and Density.
The fourth part was realized only by an introduction, The Ladder of the Understanding, or The Key to the Labyrinth; in the main work Bacon intended to expose the workings of the mind from particular to general truths in the process of invention. The fifth part is represented only by Precursors, or Anticipations of the Coming Philosophy, in which he invites all men to record facts about nature and promises to show how much he had accomplished and how much others could accomplish by using common sense and ordinary proofs without employing his method. But conclusions so reached would be regarded as tentative. The last part of the Instauration, The New Philosophy, or Active Science, would replace such conclusions and would set forth the results of applying the new method to all the phenomena of the universe. Bacon left this section unwritten, as something beyond his powers.
Such was Bacon's Grand Design: most of it was left for posterity to realize, but some particular features of the works which he accomplished toward it deserve special comment.