Prerogative Instances

²¹ After our tables of first review, our rejection or exclusive table, and the first vintage derived from them, we must advance to the remaining helps of the understanding with regard to the interpretation of nature, and a true and perfect induction.

We will treat of:

1. Prerogative instances
2. the supports of induction
3. the correction[160] of induction
4. varying the investigation according to the nature of the subject
5. the prerogative natures with respect to investigation, or of what should be the first or last objects of our research
6. the limits of investigation, or a synopsis of all natures that exist in the universe
7. the application to practical purposes, or of what relates to man
8. the preparations for investigation
9. of the ascending and descending scale of axioms.[108]

²² The first prerogative instance is solitary instance.

Solitary instances are those which exhibit the required nature in subjects that:

• have nothing in common with any other subject regarding the nature in question
• do not exhibit the required nature in resembling subjects
  • Those resembling subjects:
    • remove prolixity
    • accelerate and confirm exclusion, so that a few of them are of as much avail as many.

An example is color.

Prisms and crystalline gems yield colors:

• internally
• externally on the wall, dews, etc.

These are solitary instances. They have nothing in common with the fixed colors in flowers, metals, woods, etc. except the color itself.

Hence color is nothing but a modification of the image of the incident and absorbed light, occasioned in the former case by the different degrees of incidence, in the latter by the various textures and forms of bodies.[109]

These are solitary instances as regards similitude.

Again, in the same inquiry the distinct veins of white and black in marble, and the variegated colors of flowers of the same species, are solitary instances; for the black and white of marble, and the spots of white and purple in the flowers of the stock, agree in every respect but that of color. Thence we easily deduce that color has not much to do with the intrinsic natures of any body, but depends only on the coarser and as it were mechanical arrangement of the parts. These are solitary instances as regards difference. We call them both solitary or wild, to borrow a word from the astronomers.