Bacon titled this first book Aphorismi de Interpretatione Naturae et Regno Hominis ("Aphorisms Concerning the Interpretation of Nature, and the Kingdom of Man").
In the first book of aphorisms, Bacon criticizes the current state of natural philosophy. The object of his assault consists largely in the syllogism, a method that he believes to be completely inadequate in comparison to what Bacon calls "true Induction":
The syllogism is made up of propositions, propositions of words, and words are markers of notions. Thus if the notions themselves (and this is the heart of the matter) are confused, and recklessly abstracted from things, nothing built on them is sound. The only hope therefore lies in true Induction.
— aph. 14
In many of his aphorisms, Bacon reiterates the importance of inductive reasoning. Induction, methodologically opposed to deduction, entails beginning with particular cases observed by the senses and then attempting to discover the general axioms from those observations. In other words, induction presupposes nothing. Deduction, on the other hand, begins with general axioms, or first principles, by which the truth of particular cases is extrapolated. Bacon emphasises the strength of the gradual process that is inherent in induction:
There are and can only be two ways of investigating and discovering truth. The one rushes up from the sense and particulars to axioms of the highest generality and, from these principles and their indubitable truth, goes on to infer and discover middle axioms; and this is the way in current use. The other way draws axioms from the sense and particulars by climbing steadily and by degrees so that it reaches the ones of highest generality last of all; and this is the true but still untrodden way.
— aph. 19
After many similar aphoristic reiterations of these important concepts, Bacon presents his famous Idols.
