Within certain limits thinking begets feeling, and feeling stimulates thinking. Beyond these limits each interferes with the other. When feeling rises to the height of passion it beclouds the judgment and prevents reflection. Certain kinds of speculative thinking leave the heart cold and ultimately destroy the better emotions and the warmer affections. “It is terrible,” said the daughter of a voluminous writer on theology, “when a man feels a perpetual impulse to write. It makes him a stranger in his own house, and deprives wife and children of their husband and father.” Abstract thinking may be indulged in to the exclusion of the tastes and emotions which help to make life worth living. The oft-quoted experience of Darwin is a case in point. In his autobiography he gives his experience, showing the effect of his exclusive devotion to scientific pursuits upon his ability to enjoy poetry, music, and pictures. “Up to the age of thirty and beyond it poetry of many kinds gave me great pleasure, and even as a school-boy I took intense delight in Shakespeare, especially in the historical plays. I have also said that pictures formerly gave me considerable and music very great delight. But now for many years I cannot endure to read a line of poetry. I have tried lately to read Shakespeare, and found it so intolerably dull that it nauseated me. I have also almost lost my taste for pictures or music. Music generally sets me thinking too energetically on what I have been at work on, instead of giving me pleasure.... My mind seems to have become a kind of machine for grinding general laws out of large collections of facts; but why this should have caused the atrophy of that part of the brain alone, on which the higher tastes depend, I cannot conceive.... If I had to live my life again, I would have made a rule to read some poetry and listen to some music at least once a week; for perhaps the parts of my brain now atrophied would thus have been kept alive through use. The loss of these tastes is a loss of happiness, and may possibly be injurious to the intellect, and more probably to the moral character by enfeebling the emotional part of our nature.”[53]
Every teacher has both felt and witnessed the effect of embarrassment upon ability to think. To face an audience of a thousand people was embarrassing to some excellent thinkers like Melanchthon and Washington. On the other hand, the sight of a multitude of listening, upturned faces stimulates natures and temperaments like that of Martin Luther and Patrick Henry, causing them to think more vigorously and to feel more deeply.