Those who have claimed that everything can be known about nature have damaged philosophy and the sciences. Similarly, those skeptics who claim that nothing can be known have brought good arguments, but have not begun from good starting points or applied rules. Bacon's method on the other hand, is easy to formulate; it is to establish degrees of certainty, restrain sensation and generally reject the work of the mind that comes from it, and to construct a new route for the mind from the perceptions of the senses. The art of logic tried to achieve a similar thing, but it was too late. It fixed errors rather than revealing the truth. The one hope is to begin over again, and to control the work of the mind by machines. Human strength in any area cannot be increased without tools and machines.
We can carry out our design without belittling the ancients. Bacon has no intention of dethroning prevailing philosophy. There should be two sorts of learning, and two kinds of philosophers; one method for cultivating the sciences and a different method for discovering them. Bacon accepts that some people may not be clever enough to grasp the second method, or may have pragmatic reasons for supporting the first. Those who seek real knowledge of nature rather than opinion follow the second, however. One is called the Anticipation of Mind, the other the Interpretation of Nature. Would-be critics should follow Bacon's method first and eradicate their bad mental habits.
I–X. Man is the interpreter and agent of nature; he understands Nature through facts or inferences. The intellect needs tools to prompt and guide its motions, just like the hands. Human knowledge and power are the same thing, because ignorance of cause frustrates effect. Mechanics, mathematicians, physicians, alchemists and magicians meddle with Nature, with little effect. It is insane to think that things not yet achieved can be achieved with current methods. The creations of mind and hand look prolific, but in fact rest upon a few subtle deductions from a few known things. Current results owe more to chance than anything. The problems of modern science result from the fact that we mistakenly admire the mind without considering its true supports. The subtlety of nature exceeds that of the human mind.
XI–XX. Logic is useless for the discovery of sciences; it is harmful because it fixes errors rather than inquiring into truth. Syllogisms compel assent without reference to things; if the notions they are built on are unsound, there is no hope. The only hope is induction. There is nothing sound in the notions of logic and physics. Similar problems can occur with axioms formed by induction, but this is more common with syllogisms. Previous scientific discoveries fit into common notions; to understand nature better, axioms need to be better-grounded. There are two ways to investigate truth. The current, dialectical way goes from sense to general axioms, then finds intermediate axioms from these truths; the true way rises from sense upwards to general axioms.
XXI–XXXI. The intellect tries the other way, but cannot succeed without guidance. Both ways begin with sense and end in the general, but are very different. Only one deals fully with the particular, and rises step by step to what is truly known of nature. Axioms formed by argument are no good for discovering new results, but arguments can suggest new particulars. Current axioms come from limited common experience; therefore they do not lead to new particulars. Normal scientific reasoning is the anticipation of nature: true reasoning is the interpretation of nature. Anticipations can induce agreement more powerfully than interpretations. The use of anticipations is acceptable where assent is needed without reference to things. No great progress is possible through anticipations; a new beginning is needed.
XXXII–XLIV. The best way of teaching the new method is to introduce men to actual things, and get them to abstain from notions. Bacon's way initially agrees with the ancient skeptics, but it has different aims and ends. Skeptics destroy the authority of sense and intellect; Bacon aims to support these. Illusions and false notions will disrupt the access of truth, unless men arm themselves against them. There are four kinds of illusions: the idols of the tribe (illusions founded in human nature—human understanding merges its own nature with the nature of things and distorts them), the idols of the cave (the illusions of the individual man, due to his particular nature), the idols of the marketplace (illusions that arise from agreement and men's association with others—words and talk obstruct understanding) and the idols of the theater (illusions produced by philosophers who create false and fictitious worlds).