I ought, however, to remove some objections, that will naturally occur in reading this volume. The first is, the discourses not being distributed in determin’d classes, and not following in a regular progression, the faculties or matters to which they belong. To this I answer, that though I at first design’d such an arrangement, I soon discover’d the pursuing it to be impracticable; for having proposed to myself so vast a field in the Teatro Critico, I saw that many of the matters which would be touch’d upon in it, were incomprehensible under a determin’d faculty; either because they do not belong to any one in particular, or because, they participate equally of many. Besides, there are a number, every one of which, treats solely of some particular faculty, without any other having to do with the subject matter. On physical subjects only, within which walk the errors of the vulgar are infinite, you may write as many discourses as are capable of making a separate volume; but I am more disposed to divide them in the different volumes, because by so doing, each will afford a more agreeable variety. By this means, although every volume with respect to the matter, will appear strictly speaking, a miscellany, the design of attacking common errors will be uniformly preserved. The formal object will always be the same, the materials must necessarily be composed of great variety, and should be distributed. I may perhaps be blamed, for giving the name of errors to all the opinions I controvert. The complaint would be just, if I did not remove the odium of the term by an explanation. I say then, that error in the sense I here take and use it, signifies no more than an opinion that I look upon as false, abstracted from, and without my determining upon the probability or improbability of it. Neither by the term common errors, do I mean to signify, that those I encounter are incident to all mankind, it is sufficient to apply this term to them, if they are admitted by the generality of the vulgar, or lead in their train, a more than ordinary number of the literati. This must be understood with a reservation, that I don’t mean to introduce myself as a judge in those questions, which are mooted in various schools, especially such as regard Theological points: for what advances can I make on those subjects, which have been studied and considered with the most intense reflection, by so many men of eminence? or who am I, to have such confidence in my own strength, as to fancy that I am capable of entering the lists, where so many giants engage? In matters purely physical, this objection need not detain me; for those of this species which are treated of in other schools are very few, and those few with little or no reflection.