egen seines noch
hoeheren Grundes erfahren."--_Kritik._ Ed. Hartenstein, p. 422.

[32] _I.e._ Natural philosophers.

[33] Hume's letter to Mure of Caldwell, containing a criticism of
Leechman's sermon (Burton, I. p. 163), bears strongly on this point.

[34] Burns published the _Holy Fair_ only ten years after Hume's death.

CHAPTER IX.

THE SOUL: THE DOCTRINE OF IMMORTALITY.

Descartes taught that an absolute difference of kind separates matter,
as that which possesses extension, from spirit, as that which thinks.
They not only have no character in common, but it is inconceivable that
they should have any. On the assumption, that the attributes of the two
were wholly different, it appeared to be a necessary consequence that
the hypothetical causes of these attributes--their respective
substances--must be totally different. Notably, in the matter of
divisibility, since that which has no extension cannot be divisible, it
seemed that the _chose pensante_, the soul, must be an indivisible
entity.

Later philosophers, accepting this notion of the soul, were naturally
much perplexed to understand how, if matter and spirit had nothing in
common, they could act and react on one another. All the changes of
matter being modes of motion, the difficulty of understanding how a
moving extended material body was to affect a thinking thing which had
no dimension, was as great as that involved in solving the problem of
how to hit a nominative case with a stick. Hence, the successors of
Descartes either found themselves obliged, with the Occasionalists, to
call in the aid of the Deity, who was supposed to be a sort of
go-between betwixt matter and spirit; or they had recourse, with
Leibnitz, to the doctrine of pre-established harmony, which denied any
influence of the body on the soul, or _vice versa_, and compared matter
and spirit to two clocks so accurately regulated to keep time with one
another, that the one struck when ever the other pointed to the hour;
or, with Berkeley, they abolished the "substance" of matter altogether,
as a superfluity, though they failed to see that the same arguments
equally justified the abolition of soul as another superfluity, and the
reduction of the universe to a series of events or phenomena; or,
finally, with Spinoza, to whom Berkeley makes a perilously close
approach, they asserted the existence of only one substance, with two
chief attributes, the one, thought, and the other, extens