From An Essay on Criticism

PART II

   Of all the causes which conspire to blind
Man's erring judgment, and misguide the mind,
What the weak head with strongest bias rules,
Is pride, the never-failing vice of fools.
Whatever Nature has in worth denied,
She gives in large recruits of needful pride;
For as in bodies, thus in souls, we find
What wants in blood and spirits, swelled with wind;
Pride, where wit fails, steps in to our defence,
And fills up all the mighty void of sense!
If once right reason drives that cloud away,
Truth breaks upon us with resistless day;
Trust not yourself; but your defects to know,
Make use of every friend - and every foe.

    A little learning is a dangerous thing;
Drink deep, or taste not the Pierian spring:
There shallow draughts intoxicate the brain,
And drinking largely sobers us again.
Fired at first sight with what the Muse imparts,
In fearless youth we tempt the heights of arts,
While from the bounded level of our mind,
Short views we take, nor see the lengths behind,
But more advanced, behold with strange surprise
New, distant scenes of endless science rise!
So pleased at first, the towering Alps we try,
Mount o'er the vales, and seem to tread the sky;
The eternal snows appear already past,
And the first clouds and mountains seem the last;
But those attained, we tremble to survey
The growing labours of the lengthened way,
The increasing prospect tires our wandering eyes,
Hills peep o'er hills, and Alps on Alps arise!