We cannot conceive how anything but impulse of body can move body; and yet that is not a reason sufficient to make us deny it possible, against the constant experience we have of it in ourselves, in all our voluntary motions; which are produced in us only by the free action or thought of our own minds, and are not, nor can be, the effects of the impulse or determination of the motion of blind matter in or upon our own bodies; for then it could not be in our power or choice to alter it.

For example: my right hand writes, whilst my left hand is still: What causes rest in one, and motion in the other?
Nothing but my will,--a thought of my mind; my thought only changing, the right hand rests, and the left hand moves.

This is matter of fact, which cannot be denied: explain this and make it intelligible, and then the next step will be to understand creation.

[For the giving a new determination to the motion of the animal spirits (which some make use of to explain voluntary motion) clears not the difficulty one jot.

To alter the determination of motion, being in this case no easier nor less, than to give motion itself: since the new determination given to the animal spirits must be either immediately by thought, or by some other body put in their way by thought which was not in their way before, and so must owe ITS motion to thought: either of which leaves VOLUNTARY motion as unintelligible as it was before.] In the meantime, it is an over-valuing ourselves to reduce all to the narrow measure of our capacities; and to conclude all things impossible to be done, whose manner of doing exceeds our comprehension.