Habitual thinking is just that—­a habit.  Habit comes of doing a thing repeatedly.  The lower habits are acquired easily, the higher ones require deeper grooves if they are to persist.  So we find that the thought-habit comes only with resolute practise; yet no effort will yield richer dividends.  Persist in practise, and whereas you have been able to think only an inch-deep into a subject, you will soon find that you can penetrate it a foot.

Perhaps this homely metaphor will suggest how to begin the practise of consecutive thinking, by which we mean welding a number of separate thought-links into a chain that will hold.  Take one link at a time, see that each naturally belongs with the ones you link to it, and remember that a single missing link means no chain.

Thinking is the most fascinating and exhilarating of all mental exercises.  Once realize that your opinion on a subject does not represent the choice you have made between what Dr. Cerebrum has written and Professor Cerebellum has said, but is the result of your own earnestly-applied brain-energy, and you will gain a confidence in your ability to speak on that subject that nothing will be able to shake.  Your thought will have given you both power and reserve power.

Someone has condensed the relation of thought to knowledge in these pungent, homely lines: 

    “Don’t give me the man who thinks he thinks,
       Don’t give me the man who thinks he knows,
    But give me the man who knows he thinks,
       And I have the man who knows he knows!”

Reading As a Stimulus to Thought

No matter how dry the cow, however, nor how poor our ability to milk, there is still the milkman—­we can read what others have seen and felt and thought.  Often, indeed, such records will kindle within us that pre-essential and vital spark, the desire to be a thinker.

The following selection is taken from one of Dr. Newell Dwight Hillis’s lectures, as given in “A Man’s Value to Society.”  Dr. Hillis is a most fluent speaker—­he never refers to notes.  He has reserve power.  His mind is a veritable treasure-house of facts and ideas.  See how he draws from a knowledge of fifteen different general or special subjects:  geology, plant life, Palestine, chemistry, Eskimos, mythology, literature, The Nile, history, law, wit, evolution, religion, biography, and electricity.  Surely, it needs no sage to discover that the secret of this man’s reserve power is the old secret of our artesian well whose abundance surges from unseen depths.

THE USES OF BOOKS AND READING[9]