Your Authour discoursing of Imagination, saith,[1] _That as soon as any object is removed from our Eyes, though the Impression that is made in us remain, yet other objects more present succeeding and working on us, the Imagination of the past is obscured and made weak_. To which I answer, first, that he conceives Sense and Imagination to be all one, for he says, _Imagination is nothing else, but a fading or decaying sense_; whereas in my opinion they are different, not onely their matter, but their motions also being distinct and different; for Imagination is a rational perception, and Sense a sensitive perception; wherefore as much as the rational matter differs from the sensitive, as much doth Imagination differ from Sense. Next I say, that Impressions do not remain in the body of sensitive matter, but it is in its power to make or repeat the like figures; Neither is Imagination less, when the object is absent, then when present, but the figure patterned out in the sensitive organs, being altered, and remaining onely in the Rational part of matter, is not so perspicuous and clear, as when it was both in the Sense and in the Mind: And to prove that Imagination of things past doth not grow weaker by distance of time, as your Authour says, many a man in his old age, will have as perfect an Imagination of what is past in his younger years, as if he saw it present. And as for your Authours opinion, that _Imagination and Memory are one and the same_, I grant, that they are made of one kind of Matter; but although the Matter is one and the same, yet several motions in the several parts make Imagination and Memory several things: As for Example, a Man may Imagine that which never came into his Senses, wherefore Imagination is not one and the same thing with Memory. But your Authour seems to make all Sense, as it were, one Motion, but not all Motion Sense, whereas surely there is no Motion, but is either Sensitive or Rational; for Reason is but a pure and refined Sense, and Sense a grosser Reason. Yet all sensitive and rational Motions are not one and the same; for forced or Artificial Motions, though they proceed from sensitive matter, yet are they so different from the free and Prime Natural Motions, that they seem, as it were, quite of another nature: And this distinction neglected is the Cause, that many make Appetites and Passions, Perceptions and Objects, and the like, as one, without any or but little difference. But having discoursed of the difference of these Motions in my former Letter, I will not be tedious to you with repeating it again, but remain, Madam, _Your faithful Friend_ _and Servant._ [1] _Leviathan, part._ 1. _c._ 2. VII. _MADAM,_