68 All idols must be abjured and renounced.
The understanding must be completely cleared of them, so that the access to the kingdom of man, which is founded on the sciences, may resemble that to the kingdom of heaven, where no admission is conceded except to children.
69 Vicious demonstrations are the muniments and support of idols, and those which we possess in logic, merely subject and enslave the world to human thoughts, and thoughts to words.
But demonstrations are themselves systems of philosophy and science.
; for such as they are, and accordingly as they are regularly or improperly established, such will be the resulting systems of philosophy and contemplation. But those which we employ in the whole process leading from the senses and things to axioms and conclusions, are fallacious and incompetent.
This process is fourfold, and the errors are in equal number.
- The impressions of the senses are erroneous
They fail and deceive us. We must supply defects by substitutions, and fallacies by their correction.
Notions are improperly abstracted from the senses, and indeterminate and confused when they ought to be the reverse.
The induction that is employed is improper
It determines the principles of sciences by simple enumeration, without adopting exclusions and resolutions, or just separations of nature.
- The usual method of discovery and proof is the parent of error and the calamity of every science.
It first establishes the most general propositions. Then it applies and proves the intermediate axioms according to them.
70 But experience is by far the best demonstration, provided it adhere to the experiment actually made, for if that experiment be transferred to other subjects apparently similar, unless with proper and methodical caution it becomes fallacious.
The present method of experiment is blind and stupid; hence men wandering and roaming without any determined course, and consulting mere chance, are hurried about to various points, and advance but little—at one time they are happy, at another their attention is distracted, and they always find that they want something further.
Men generally make their experiments carelessly, and as it were in sport, making some little variation in a known experiment, and then if they fail they become disgusted and give up the attempt; nay, if they set to work more seriously, steadily, and assiduously, yet they waste all their time on probing some solitary matter, as Gilbert on the magnet, and the alchemists on gold.
But such conduct shows their method to be no less unskilful than mean; for nobody can successfully investigate the nature of any object by considering that object alone; the inquiry must be more generally extended.
Even when men build any science and theory upon experiment, yet they almost always turn with premature and hasty zeal to practice, not merely on account of the advantage and benefit to be derived from it, but in order to seize upon some security in a new undertaking of their not employing the remainder of their labor unprofitably, and by making themselves conspicuous, to acquire a greater name for their pursuit.
Hence, like Atalanta, they leave the course to pick up the golden apple, interrupting their speed, and giving up the victory.
But in the true course of experiment, and in extending it to new effects, we should imitate the Divine foresight and order; for God on the first day only created light, and assigned a whole day to that work without creating any material substance thereon.
Similarly, we must first, by every kind of experiment:
- elicit the discovery of causes and true axioms
- seek for experiments which may afford light rather than profit.
Axioms, when rightly investigated and established, prepare us not for a limited but abundant practice, and bring in their train whole troops of effects.
But we will treat hereafter of the ways of experience, which are not less beset and interrupted than those of judgment; having spoken at present of common experience only as a bad species of demonstration, the order of our subject now requires some mention of those external signs of the weakness in practice of the received systems of philosophy and contemplation which we referred to above, and of the causes of a circumstance at first sight so wonderful and incredible. For the knowledge of these external signs prepares the way for assent, and the explanation of the causes removes the wonder; and these two circumstances are of material use in extirpating more easily and gently the idols from the understanding.