I did not write this Book out of delight, love or humour to contradiction; for I would rather praise, then contradict any Person or Persons that are ingenious; but by reason Opinion is free, and may pass without a pass-port, I took the liberty to declare my own opinions as other Philosophers do, and to that purpose I have here set down several famous and learned Authors opinions, and my answers to them in the form of Letters, which was the easiest way for me to write; and by so doing, I have done that, which I would have done unto me; for I am as willing to have my opinions contradicted, as I do contradict others: for I love Reason so well, that whosoever can bring most rational and probable arguments, shall have my vote, although against my own opinion. But you may say, If contradictions were frequent, there would be no agreement amongst Mankind. I answer; it is very true: Wherefore Contradictions are better in general Books, then in particular Families, and in Schools better then in Publick States, and better in Philosophy then in Divinity. All which considered, I shun, as much as I can, not to discourse or write of either Church or State. But I desire so much favour, or rather Justice of you, _Worthy Readers_, as not to interpret my objections or answers any other ways then against several opinions in Philosophy; for I am confident there is not any body, that doth esteem, respect and honour learned and ingenious Persons more then I do: Wherefore judg me neither to be of a contradicting humor, nor of a vain-glorious mind for differing from other mens opinions, but rather that it is done out of love to Truth, and to make my own opinions the more intelligible, which cannot better be done then by arguing and comparing other mens opinions with them. The Authors whose opinions I mention, I have read, as I found them printed, in my native Language, except _Des Cartes_, who being in Latine, I had some few places translated to me out of his works; and I must confess, that since I have read the works of these learned men, I understand the names and terms of Art a little better then I did before; but it is not so much as to make me a Scholar, nor yet so little, but that, had I read more before I did begin to write my other Book called _Philosophical Opinions_, they would have been more intelligible; for my error was, I began to write so early, that I had not liv'd so long as to be able to read many Authors; I cannot say, I divulged my opinions as soon as I had conceiv'd them, but yet I divulged them too soon to have them artificial and methodical. But since what is past, cannot be recalled, I must desire you to excuse those faults, which were committed for want of experience and learning. As for School-learning, had I applied my self to it, yet I am confident I should never have arrived to any; for I am so uncapable of Learning, that I could never attain to the knowledge of any other Language but my native, especially