One of the most prevalent defects of judgment is illustrated in this common disability to select premises which fit the facts. Ignorance, emotional reasoning, and a defective critical sense probably explain most poor judgments.
The other judgment illustrates the logic of correct, provable premises.
“No, I shall wait until dinner-time. I have no need of so rich a food, for I had an adequate meal at the usual time and have not worked hard enough to justify adding this burden to my digestive apparatus; besides only hard workers with their muscles can afford to eat many sweets. They cause an overacid condition when taken in excess; and any except at mealtimes would be excess for me, with my moderate physical exercise.”
This judgment we call good. Its premises correspond to scientific facts.
But much reasoning must always be done with probable premises, ones which seem to correspond to the facts, but which have yet to be proved. And our judgment from such suppositions cannot be final until we see if it works.
Some few centuries ago supposedly wise men called Christopher Columbus a fool. Of course the world was flat. If it were round man would fall off. It was all spread out and the oceans were its limits. If it should be round, like a ball, as that mad man claimed, then the waters must reach from Europe ’round the sphere and touch Asia; or there might be land out there beyond the ocean’s curve. But it wasn’t round, and the idea of finding a new way to Asia by sailing in the opposite direction was a fool’s delusion.
Their logic was perfect. If the earth was flat, and Asia lay east of Europe, it was madness to sail west to reach it. But they argued from a wrong premise, so their judgment was imperfect—for they did not yet know the facts.
The result of all reasoning is judgment. And judgment is good as the materials of the reasoning process correspond to facts, or are in line with the most probable of the yet unknown. It is poor as the reasoning material fails to meet the facts, or is out of harmony with the most probable of the yet unproved.
It is of no avail, then, to attempt to improve our final judgments as such. We must examine the materials we reason with, then learn to group and compare them logically. And in the very separating of true premises from false, we use and train the judgment we would improve. And this the normal mind can do.