From Spencer, London "learned that the right symbols were the ones that would require the expenditure of the minimum of my reader’s brain energy, leaving the maximum of his brain energy to realize and enjoy the content of my mind, as conveyed to his mind.”
Foreseeing today's attention-deficient audiences, Spencer preached "the importance of economizing the reader's or hearer's attention, to so present ideas that they may be apprehended with the least possible mental effort."
Spencer insists, "the more time and attention it takes to receive and understand each sentence, the less time and attention can be given to the contained idea; and the less vividly will that idea be conceived."
To compensate for audiences' sparse mental energy, writers and speakers should economize; or, as Spencer suggests, follow "the law of easy apprehension."
I've boiled his law down to six tips:
1. Avoid long, Latinate words. Use instead the short Anglo-Saxon ones we learned as kids. Use Latinate words only to express big ideas, because "a voluminous, mouth-filling epithet is, by its very size, suggestive of largeness or strength," and "allows the hearer's consciousness a longer time to dwell upon the quality predicated."
2. Use words that sound like their meanings. "Both those directly imitative, as splash, bang, whiz, roar; and those analogically imitative, as rough, smooth, keen, blunt, thin, hard, crag; have a greater or less likeness to the things symbolized; and by making on the senses impressions allied to the ideas to be called up, they save part of the effort needed to call up such ideas, and leave more attention for the ideas themselves."
3. Use specific, instead of generic, words. "If, by employing a specific term, an appropriate image can be at once suggested, an economy is achieved, and a more vivid impression produced.
4. Watch your word sequence. The order of your words should allow readers' or listeners' brains to process each as it arrives, with minimum effort. Put subjects in front of predicates, and give priority to big ideas by placing them at the front of the sentence. "The right formation of a picture will be facilitated by presenting its elements in the order in which they are wanted; even though the mind should do nothing until it has received them all."
5. Place subordinate parts of a sentence ahead of the main part. "Containing, as the subordinate proposition does, some qualifying or explanatory idea, its priority prevents misconception of the principal one; and therefore saves the mental effort needed to correct such misconception."
6. Place related words and expressions near one another. "The longer the time that elapses between the mention of any qualifying member and the member qualified, the longer must the mind be exerted in carrying forward the qualifying member ready for use. And the more numerous the qualifications to be simultaneously remembered and rightly applied, the greater will be the mental power expended, and the smaller the effect produced."
Don't have the energy to read Herbert Spencer's The Philosophy of Style?
Good news: there's a free audiobook.