Page:The Works of Francis Bacon (1884) Volume 1.djvu/89

 but, as natural and experimental history is so copious and diffusive as to confound and distract the understanding, unless digested in proper order, tallies are formed and so digested, that the understanding may commodiously work upon them.

The first, or Affirmative Table, consists of a general collection of all the known analogous instances which agree in the nature sought, from subjects however dissimilar or sordid they may be supposed to be, and without being deterred by the apparent number of particulars. If, for instance, the nature sought be heat or light, these tables may be thus conceived:

Such is the object of his first or affirmative table, which, he warns his reader, is not to raise the edifice, but merely to collect the materials, and which is, therefore, to be made without any hasty indulgence of speculation, although the mind may, in proportion to its ingenuity, accidentally, from an inspection of affirmative instances, arrive at a just conclusion.

The second, or Negative Table, consists of a collection of all the known instances of similar bodies, which do not agree in the same nature. Thus, let the nature sought be heat.

By observing this table, it appears that the blood of all animals is not hot. This table, therefore, prevents hasty generalization: "As if Samuel should have rested in those sons of Jesse which were brought before him in the house, and should have sought David, who was absent in the field."

By observing the table, it also appears, that boiling water is hot; ice is cold:—living bodies are hot; dead bodies are cold;—but in boiling water and in living bodies there is motion of parts: in ice and dead bodies they are fixed. Another use, therefore, of this table is to discover the nature sought by observing its qualities which are absent in the analogous nature, "like the images of Cassius and Brutus, in the funeral of Junia;" of which, not being represented as many others were, Tacitus saith, "Eo ipso præfulgebant quod non visebantur."

The third, or Table of Comparisons, consists of comparison of quantity of the nature sought in the same bodies and in different bodies. Thus,

By observing this table the cause of the different quantities of the nature sought, some approximation may be made to the nature itself. Thus, vegetables, or common water, do not exhibit heat to the touch, but masticated pepper or boiling water are hot. Flame is hotter than the human body: boiling water than warm. Is there any difference except in the motion of the parts?

Or of Exclusions, is of a more complicated nature. Bacon assumes that the quality of any nature can be ascertained by its being always present when the sought nature is present: is always absent when the sought nature is absent: increases always with its increase, and decreases with its decrease.

Upon this principle his table of exclusion is formed, by excluding, 1st, Such particular natures as are not found in any instances where the given nature is present; or, 2d, Such as are found in any instances where that nature is absent; and 3d,