all hope of
immortality pronounces the phrase, "Thought is a function of the brain,"
he thinks of the matter just as he thinks when he says, "Steam is a
function of the teakettle," "Light is a function of the electric
circuit," "Power is a function of the moving waterfall." In these latter
cases the several material objects have the function of inwardly
creating or engendering their effects, and their function must be called
_productive_ function. Just so, he thinks, it must be with the brain.
Engendering consciousness in its interior, much as it engenders
cholesterin and creatin and carbonic acid, its relation to our soul's
life must also be called productive function. Of course, if such
production be the function, then when the organ perishes, since the
production can no longer continue, the soul must surely die. Such a
conclusion as this is indeed inevitable from that particular conception
of the facts.

Rut in the world of physical nature productive function of this sort is
not the only kind of function with which we are familiar. We have also
releasing or permissive function; and we have transmissive function.

The trigger of a crossbow has a releasing function: it removes the
obstacle that holds the string, and lets the bow fly back to its natural
shape. So when the hammer falls upon a detonating compound. By knocking
out the inner molecular obstructions, it lets the constituent gases
resume their normal bulk, and so permits the explosion to take place.

In the case of a colored glass, a prism, or a refracting lens, we have
transmissive function. The energy of the light, no matter how produced,
is by the glass sifted and limited in color, and by the lens or prism
determined to a certain path and shape. Similarly, the keys of an organ
have only a transmissive function. They open successively the various
pipes and let the wind in the air chest escape in various ways. The
voices of the various pipes are constituted by the columns of air
trembling as they emerge. But the air is not engendered in the organ.
The organ proper, as distinguished from its air chest, is only an
apparatus for letting portions of It loose upon the world in these
peculiarly limited shapes.

My thesis now is this: that, when we think of the law that thought is a
function of the brain, we are not required to think of productive
function only; _we are entitled also to consider permissive or
transmissive function_. And this the ordinary psychop