ASTRONOMY. 
213 
see nothing but bright points, luminous circles, or the 
phases of spheres reflecting the light which falls upon them. 
Now we deduce design from relation, aptitude, and cor¬ 
respondence of parts. Some degree therefore of com¬ 
plexity is necessary to render a subject fit for this species 
of argument. But the heavenly bodies do not, except per¬ 
haps in the instance of Saturn’s ring, present themselves to 
our observation as compounded of parts at all. This, 
which may be a perfection in them, is a disadvantage to us, 
as inquirers after their nature. They do not come within 
our mechanics. 
And what we say of their forms, is true of their motions. 
Their motions are carried on without any sensible interme¬ 
diate apparatus; whereby we are cut off from one principal 
ground of argumentation—analogy. We have nothing 
wherewith to compare them; no invention, no discovery, 
no operation or resource of art, which, in this respect, 
resembles them. Even those things whieh are made to im¬ 
itate and represent them, such as orreries, planetaria, celes¬ 
tial globes, &.c. bear no affinity to them, in the cause and 
principle by which their motions are actuated. I can as¬ 
sign for this difference a reason of utility, viz. a reason why, 
though the action of terrestrial bodies upon each other be, 
in almost all cases, through the intervention of solid or 
fluid substances, yet central attraction does not operate in 
this manner. It was necessary that the intervals between 
the planetary orbs should be devoid of any inert matter 
either fluid or solid, because such an intervening substance 
would, by its resistance, destroy those very motions which 
attraction is employed to preserve. This may be a final 
cause of the difference; but still the difference destroys 
the analogy .* 
Our ignorance, moreover, of the sensitive natures by 
which other planets are inhabited, necessarily keeps from 
us the knowledge of numberless utilities, relations, and 
subserviencies, which we perceive upon our own globe. 
After all; the real subject of admiration is, that we un¬ 
derstand so much of astronomy as we do. That an animal 
confined to the surface of one of the planets; bearing a 
♦ The moon has no perceptible atmosphere: and as no effects have 
been observed like those whieh would be produced by vapors or exhala¬ 
tions from its surface, it is possible that there are no fluids upon it. 
There is no reason, however, from these circumstances, for denying the 
existence of sensitive beings upon it, although they must be very dif¬ 
ferently constituted from ourselves, to whom air and water are essentially 
necessary.— Paxton. 
