We ought to compare our subject with things of a similar nature, and even with things of a contrary nature; for discoveries may be, and often are made by the contrast, which would escape us on the single view.

The greater number of the comparisons we make, the more general and the more certain our knowledge is likely to prove, as built upon a more extensive and perfect induction.
If an inquiry thus carefully conducted should fail at last of discovering the truth, it may answer an end perhaps as useful, in discovering to us the weakness of our own understanding.

If it does not make us knowing, it may make us modest.

If it does not preserve us from error, it may at least from the spirit of error; and may make us cautious of pronouncing with positiveness or with haste, when so much labor may end in so much uncertainty.
I could wish that, in examining this theory, the same method were pursued which I endeavored to observe in forming it.

The objections, in my opinion, ought to be proposed, either to the several principles as they are distinctly considered, or to the justness of the conclusion which is drawn from them.