We all stand in the midst of a continuous accretion of facts and experiences and the evolution of truth. The body of human knowledge is forever incomplete, but forever growing. We can see no possible end to its expansion, no prospect of its becoming final. Thus the vitally important thing is not this or that scientific discovery or the materialities of life that flow from it, but the attitude of mind, the mode of thinking without trammel, that makes for the discovery and acceptance of new truth.
"I am part of all that I have met;
Yet all experience is an arch wherethro'
Gleams that untravelled world whose margin fades
Forever and forever when I move.
How dull it were to pause, to make an end,
To rest unburnish'd, not to shine in use!
As tho' to breathe were life! Life piled on life
Were all too little, and of one to me
Little remains, but every hour is saved
From that eternal silence, something more,
A bringer of new things, and vile it were
For some three suns to store and hoard myself
And this gray spirit yearning in desire
To follow knowledge, like a sinking star,
Beyond the utmost bound of human thought."
As to any final meanings, science requires a hardy renunciation. What can be known, let us seek with all vigor and honesty of means at our disposal; what cannot be known, let us face fearlessly and no less honestly. There clearly emerges then this profoundly significant fact: our entire modern civilization rests upon a technology which has grown out of pure science, which is dependent upon a race of men who deliberately and unswervingly refuse to consider their own "desires, tastes, and interests as affording a key to the understanding of the world."
The biological purpose of intelligence, namely, to achieve adaptation to the environment, is defeated if an erroneous belief is held, for belief in unreal things closes instead of leaving open the way to new adaptations. Yet error is common because belief is the easiest way for the mind. It seems as natural for the mind to believe a thing asserted or suggested as it is for the senses to feel or sense, as every professional advertiser and politician well knows. There is no physiological equilibrium unless the mind comes to rest in a conclusion with reference to a series of conditions before it. The untrained mind reaches conclusions quickly, for this is following the line of least resistance; and superstitions represent beliefs adopted to free the mind from the strain of uncompleted thinking.
