distance, and will measure that difference. Nor could we imagine any
exception to these inferences from A or from B, whichever of the two
were assumed, unless through optical laws that might not equally affect
objects under different circumstances; I mean, for instance, that might
suffer a disturbance as applied under hypoth. B, to different depths in
space, or under hypoth. A, to different arrangements of structure in
the star. But thirdly, it is certain, that neither A nor B is the
abiding law: and next it becomes an object by science and by
instruments to distinguish more readily and more certainly between the
cases where the distance has degraded the size, and the cases where the
size being _really_ less, has caused an exaggeration of the
distance: or again, where the size being really less, yet co-operating
with a distance really greater, may degrade the estimate, (though
travelling in a right direction,) below the truth; or again where the
size being really less, yet counteracted by a distance also less, may
equally disturb the truth of human measurements, and so on.

A second large order of equivocating appearances will arise,--not as to
magnitude, but as to motion. If it could be a safe assumption, that the
system to which our planet is attached were absolutely fixed and
motionless, except as regards its own _internal_ relations of
movement, then every change outside of us, every motion that the
registers of astronomy had established, would be objective and not
subjective. It would be safe to pronounce at once that it was a motion
in the object contemplated, _not_ in the subject contemplating.
Or, reversely, if it were safe to assume as a universal law, that no
motion was possible in the starry heavens, then every change of
relations in space, between ourselves and them, would indicate and
would measure a progress, or regress, on the part of our solar system,
in certain known directions. But now, because it is not safe to rest in