its properties perceivable to the soul。 Whence it plainly follows
that it is immediately some contiguous substance； which；
operating on the eye； occasions a perception of colours： and such
is light。
。 Howl is light then a substance？
。。 I tell you； Philonous； external light is nothing but
a thin fluid substance； whose minute particles being agitated
with a brisk motion； and in various manners reflected from the
different surfaces of outward objects to the eyes； communicate
different motions to the optic nerves； which； being propagated to
the brain； cause therein various impressions； and these are
attended with the sensations of red； blue； yellow； &c。
。 It seems then the light doth no more than shake the
optic nerves。 ｛187｝
。 Nothing else。
。 And consequent to each particular motion of the
nerves； the mind is affected with a sensation； which is some
particular colour。
。 Right。
。 And these sensations have no existence without the
mind。
。 They have not。
。 How then do you affirm that colours are in the
light； since by you understand a corporeal substance
external to the mind？
。 Light and colours； as immediately perceived by us； I
grant cannot exist without the mind。 But in themselves they are
only the motions and configurations of certain insensible
particles of matter。
。 Colours then； in the vulgar sense； or taken for the
immediate objects of sight； cannot agree to any but a perceiving
substance。
。 That is what I say。
。 Well then； since you give up the point as to those
sensible qualities which are alone thought colours by all mankind
beside； you may hold what you please with regard to those
invisible ones of the philosophers。 It is not my business to
dispute about ； only I would advise you to bethink
yourself； whether； considering the inquiry we are upon； it be
prudent for you to affirm ； 。 Are not these shocking
notions； and are not they subject to as many ridiculous
inferences； as those you were obliged to renounce before in the
case of sounds？
。 I frankly own； Philonous； that it is in vain to
longer。 Colours； sounds； tastes； in a word all those termed
； have certainly no existence without the
mind。 But by this acknowledgment I must not be supposed to
derogate； the reality of Matter； or external objects； seeing it
is no more than several philosophers maintain； who nevertheless
are the farthest imaginable from denying Matter。 For the clearer
understanding of this； you must know sensible qualities are by
philosophers divided into and 。 The former
are Extension； Figure； Solidity； Gravity； Motion； and Rest； ｛188｝
and these they hold exist really in bodies。 The latter are those
above enumerated； or； briefly； ； which they assert are only so many sensations or ideas
existing nowhere but in the mind。 But all this； I doubt not； you
are apprised of。 For my part； I have been a long time sensible
there was such an opinion current among philosophers； but was
never thoroughly convinced of its truth until now。
。 You are still then of opinion that and
inherent in external unthinking substances？
。 I am。
。 But what if the same arguments which are brought
against Secondary Qualities will hold good against these also？
。 Why then I shall be obliged to think； they too exist
only in the mind。
。 Is it your opinion the very figure and extension
which you perceive by sense exist in the outward object or
material substance？
。 It is。
。 Have all other animals as good grounds to think the
same of the figure and extension which they see and feel？
。 Without doubt； if they have any thought at all。
。 Answer me； Hylas。 Think you the senses were bestowed
upon all animals for their preservation and well…being in life？
or were they given to men alone for this end？
。 I make no question but they have the same use in all
other animals。
。 If so； is it not necessary they should be enabled by
them to perceive their own limbs； and those bodies which are
capable of harming them？
。 Certainly。
。 A mite therefore must be supposed to see his own
foot； and things equal or even less than it； as bodies of some
considerable dimension； though at the same time they appear to
you scarce discernible； or at best as so many visible points？
。 I cannot deny it。
。 And to creatures less than the mite they will seem
yet larger？
。 They will。
。 Insomuch that what you can hardly discern will to
another extremely minute animal appear as some huge mountain？
｛189｝
。 All this I grant。
。 Can one and the same thing be at the same time in
itself of different dimensions？
。 That were absurd to imagine。
。 But； from what you have laid down it follows that
both the extension by you perceived； and that perceived by the
mite itself； as likewise all those perceived by lesser animals；
are each of them the true extension of the mite's foot； that is
to say； by your own principles you are led into an absurdity。
。 There seems to be some difficulty in the point。
。 Again； have you not acknowledged that no real
inherent property of any object can be changed without some
change in the thing itself？
。 I have。
。 But； as we approach to or recede from an object； the
visible extension varies； being at one distance ten or a hundred
times greater than another。 Doth it not therefore follow from
hence likewise that it is not really inherent in the object？
。 I own I am at a loss what to think。
。 Your judgment will soon be determined； if you will
venture to think as freely concerning this quality as you have
done concerning the rest。 Was it not admitted as a good argument；
that neither heat nor cold was in the water； because it seemed
warm to one hand and cold to the other？
。 It was。
。 Is it not the very same reasoning to conclude； there
is no extension or figure in an object； because to one eye it
shall seem little； smooth； and round； when at the same time it
appears to the other； great； uneven； and regular？
。 The very same。 But does this latter fact ever happen？
。 You may at any time make the experiment； by looking
with one eye bare； and with the other through a microscope。
。 I know not how to maintain it； and yet I am loath to
give up ； I see so many odd consequences following
upon such a concession。
。 Odd； say you？ After the concessions already made； I
hope you will stick at nothing for its oddness。 ＇But； on the
other hand； should it not seem very odd； if the general reasoning
｛190｝ which includes all other sensible qualities did not also
include extension？ If it be allowed that no idea； nor anything
like an idea； can exist in an unperceiving substance； then surely
it follows that no figure； or mode of extension； which we can
either perceive； or imagine； or have any idea of； can be really
inherent in Matter； not to mention the peculiar difficulty there
must be in conceiving a material substance； prior to and distinct
from extension to be the of extension。 Be the
sensible quality what it will figure； or sound； or colour； it
seems alike impossible it should subsist in that which doth not
perceive it。＇＇2＇
。 I give up the point for the present； reserving still
a right to retract my opinion； in case I shall hereafter discover
any false step in my progress to it。
。 That is a right you cannot be denied。 Figures and
extension being despatched； we proceed next to 。 Can a
real motion in any external body be at the same time very swift
and very slow？
。 It cannot。
。 Is not the motion of a body swift in a reciprocal
proportion to the time it takes up in describing any given space？
Thus a body that describes a mile in an hour moves three times
faster than it would in case it described only a mile in three
hours。
。 I agree with you。
。 And is not time measured by the succession of ideas
in our minds？
。 It is。
。 And is it not possible ideas should succeed one
another twice as fast in your mind as they do in mine； or in that
of some spirit of another kind？
。 I own it。
。 Consequently the same body may to another seem to
perform its motion over any space in half the time that it doth
to you。 And the same reasoning will hold as to any other
proportion： that is to say； according to your principles （since
the motions perceived are both really in the object） it is
possible one and the same body shall be