substances of the natural world of their very nature react against the
substances of the spiritual world; for substances of the natural world
are in themselves dead, and are acted upon from without by substances of
the spiritual world; and substances which are dead, and which are acted
upon from without, by their nature resist, and thus by their nature
react. From all this it can be seen that the natural man reacts against
the spiritual man, and that there is combat. It is the same thing whether
the terms "natural and spiritual man" or "natural and spiritual mind"
are used.

261. From this it is obvious that when the spiritual mind is closed the
natural mind continually acts against the things of the spiritual mind,
fearing lest anything should flow in therefrom to disturb its own states.
Everything that flows in through the spiritual mind is from heaven, for
the spiritual mind in its form is a heaven; while everything that flows
into the natural mind is from the world, for the natural mind in its form
is a world. From which it follows that when the spiritual mind is closed,
the natural mind reacts against all things of heaven, giving them no
admission except so far as they are serviceable to it as means for
acquiring and possessing the things of the world. And when the things
of heaven are made to serve the natural mind as means to its own ends,
then those means, though they seem to be heavenly, are made natural; for
the end qualifies them, and they become like the knowledges of the
natural man, in which interiorly there is nothing of life. But as things
heavenly cannot be so joined to things natural that the two act as one,
they separate, and, with men merely natural, things heavenly arrange
themselves from without, in a circuit about the natural things which are
within. From this it is that a merely natural man can speak and preach
about heavenly things, and even simulate them in his actions, though
inwardly he thinks against them; the latter he does when alone, the