_MADAM,_
Concerning _Sense_ and _Perception_, your _Authors_ opinion is,[1]
That it is made by a _motion or impression from the object upon the
sensitive organ, which impression, by means of the nerves, is brought
to the brain, and so to the mind or soul, which onely perceives in
the brain_: Explaining it by the example[2] of a Man being blind, or
walking in dark, who by the help of his stick can perceive when he
touches a Stone, a Tree, Water, Sand, and the like; which example he
brings to make a comparison with the perception of Light; _For_, says
he, _Light in a shining body, is nothing else but a quick and lively
motion or action, which through the air and other transparent bodies
tends towards the eye, in the same manner as the motion or resistance
of the bodies, the blind man meets withal, tends thorow the stick
towards the hand; wherefore it is no wonder that the Sun can display
its rays so far in an instant, seeing that the same action, whereby
one end of the stick is moved, goes instantly also to the other end,
and would do the same if the stick were as long as Heaven is distant
from Earth._ To which I answer first, That it is not onely the Mind
that perceives in the kernel of the Brain, but that there is a double
perception, rational and sensitive, and that the mind perceives by
the rational, but the body and the sensitive organs by the sensitive
perception; and as there is a double perception, so there is also a
double knowledg, rational and sensitive, one belonging to the mind, the
other to the body; for I believe that the Eye, Ear, Nose, Tongue, and
all the Body, have knowledg as well as the Mind, onely the rational
matter, being subtil and pure, is not incumbred with the grosser part
of matter, to work upon, or with it, but leaves that to the sensitive,
and works or moves onely in its own substance, which makes a difference
between thoughts, and exterior senses. Next I say, That it is not the
Motion or Reaction of the bodies, the blind man meets withal, which
makes the sensitive perception of these objects, but the sensitive
corporeal motions in the hand do pattern out the figure of the Stick,
Stone, Tree, Sand, and the like. And as for comparing the perception
of the hand, when by the help of the stick it perceives the objects,
with the perception of light, I confess that the sensitive perceptions
do all resemble each other, because all sensitive parts of matter are
of one degree, as being sensible parts, onely there is a difference
according to the figures of the objects presented to the senses; and
there is no better proof for perception being made by the sensitive
motions in the body, or sensitive organs, but that all these sensitive
perceptions are alike, and resemble one another; for if they were not
made in the body of the sentient, but by the impression of exterior
objects, there would be so much difference betwixt them, by reason of
the diversity of objects, as they would have no resemblance at all.
But for a further proof of my own opinion, did the perception proceed
meerly from the motion, impression and resistance of the objects, the
hand could not perceive those objects, unless they touched the hand it
self, as the stick doth; for it is not probable, that the motions of
the stone, water, sand, &c. should leave their bodies and enter into
the stick, and so into the hand; for motion must be either something
or nothing; if something, the stick and the hand would grow bigger,
and the objects touched less, or else the touching and the touched must
exchange their motions, which cannot be done so suddenly, especially
between solid bodies; But if motion has no body, it is nothing, and
how nothing can pass or enter or move some body, I cannot conceive.
'Tis true there is no part that can subsist singly by it self, without
dependance upon each other, and so parts do always joyn and touch
each other, which I am not against; but onely I say perception is not
made by the exterior motions of exterior parts of objects, but by
the interior motions of the parts of the body sentient. But I have
discoursed hereof before, and so I take my leave, resting,
Madam,
_Your faithful Friend_
_and Servant._
[1] _Philos. part._ 4. _a._ 189.
[2] _Diopt. c._ 1. _a._ 2, 3. & _c._ 4. _a._ 1.