3. As a body leaves a phantasm of its magnitude in the mind, so also a moved body leaves a phantasm of its motion, namely, an idea of that body passing out of one space into another by continual succession. And this idea, or phantasm, is that, which (without receding much from the common opinion, or from _Aristotle's_ definition) I call _Time_. For seeing all men confess a year to be time, and yet do not think a year to be the accident or affection of any body, they must needs confess it to be, not in the things without us, but only in the thought of the mind. So when they speak of the times of their predecessors, they do not think after their predecessors are gone, that their times can be any where else than in the memory of those that remember them. And as for those that say, days, years, and months are the motions of the sun and moon, seeing it is all one to say, motion _past_ and motion _destroyed_, and that _future_ motion is the same with motion which _is not yet begun_, they say that, which they do not mean, that there neither is, nor has been, nor shall be any time: for of whatsoever it may be said, _it has been_ or _it shall be_, of the same also it might have been said heretofore, or may be said hereafter, _it is_. What then can days, months, and years, be, but the names of such computations made in our mind? _Time_ therefore is a phantasm, but a phantasm of motion, for if we would know by what moments time passes away, we make use of some motion or other, as of the sun, of a clock, of the sand in an hour-glass, or we mark some line upon which we imagine something to be moved, there being no other means by which we can take notice of any time at all. And yet, when I say _time_ is a phantasm of motion, I do not say this is sufficient to define it by; for this word _time_ comprehends the notion of _former_ and _latter_, or of _succession_ in the motion of a body, in as much as it is first _here_ then _there_. Wherefore a complete definition of _time_ is such as this, TIME _is the phantasm of before and after in motion_; which agrees with this definition of _Aristotle_, _time is the number of motion according to former and latter_; for that numbering is an act of the mind; and therefore it is all one to say, _time is the number of motion according to former and latter_; and _time is a phantasm of motion numbered_. But that other definition, _time is the measure of motion_, is not so exact, for we measure time by motion and not motion by time. [Sidenote: Part.] 4. One space is called _part_ of another space, and one time _part_ of another time, when this contains that and something besides. From whence it may be collected, that nothing can rightly be called a PART, but that which is compared with something that contains it. [Sidenote: Division.]