Coherence refers to the combining of different elements or parts into an orderly, consistent, or logical whole.
Papers, paragraphs, speeches, politics, theories, and cultures are just a few of the things that are frequently described as possessing (or lacking) coherence.
Possessing coherence or being coherent are almost always terms of praise, suggesting that parts or pieces of some larger whole are connected in a logical or understandable way.
The higher the climber went up the mountain, the more deprived her brain was of of oxygen. As a result, her recorded messages began to lose their previous coherence.
The speech lacked all coherence, with the obviously nervous speaker jumping from one rambling, unrelated thought to another.
Coherence in a text is created as much by the reader as it is by the writer.
Developing a sense of cultural coherence is particularly important to children whose parents were born in a very different country from where the children were born and are being schooled.
He called himself a "political activist," but since his political goals were without any obvious coherence, she didn't know what that label might mean in practical terms.
Memory Peg. The prefix "co" can mean "together," as in coproduction or indicate a partner as in copilot. Use your knowledge of that prefix to remember that speeches, theories, or ideas with coherence all have parts that fit "together" in a way that makes sense. The different parts or elements "partner" up effectively because there is a logical connection between them.
Specialized Use in Writing and Composition. Writing is often praised or faulted due to the presence or absence of coherence. Coherent writing makes readers experience an author's text as focused and unified. It communicates a central message or experience. Writer and journalist Tom Ashbrook, for instance, has mastered the art of creating coherence. Here he writes about author Richard Rodriguez:
In the age of rampant blogs and social media, everybody has a voice. But few are singular. Rodriguez is singular. The rare mind and eye that sees and communicates on its own deeply humane terms. He's gay, he's Catholic, he's Hispanic, he's a serious man. And he is wide open to the world, all of it. Thinking deeply about faith, people, place. Deserts and visions. Men and women and their roles. Women especially, and their challenge to patriarchy. He's been called the most empathetic essayist in America.
[Source.
Last accessed on February 22, 2014]
Ashbrook thinks that Rodriguez is a "singular" man, one of a kind, unique. Every sentence he writes works to communicate that point. That's what makes his writing coherent.
Writing lacking in coherence is very different. It leaves the reader wondering what exactly the author wants to say. At best, the reader ends up knowing the topic but with little sense of what the author wanted to say about the topic.
The dean of academic writing Joseph M. Williams offers a good example of writing lacking in coherence:
Saner, Wisconsin is the snowmobile capital of the world. The buzzing of snowmobile engines fills the air, and their tank like tracks crisscross the snow. The snow reminds me of Mom's mashed potatoes, covered with furrows I would draw with my fork. Mom's mashed potatoes usually made me sick, that's why I played with them. I like to make a hole in the middle of the potatoes and fill it with melted butter. This behavior has been the subject of long chats between me and my analyst.
[Joseph M. Williams, Style: Ten Lessons in Clarity and Grace, 6e, p.103]
The author of that paragraph probably has a point about snowmobiles, mashed potatoes, or chats with his analyst. But he hasn't shaped the text in a way that makes the reader able to follow along and figure out what that point is. That's what makes the writing lack coherence.
Specialized Use in Science.
Scientists talk about the coherence of light. The term refers to light waves and the way they do or do not match each other in distance and form. Coherent sources of light produce continuous light waves of the same length or distance apart and are in synch, or in "phase," with one another.
Two light waves are said to be coherent if the peaks of one light wave match the peaks of the other and the troughs, or depressions, of the light waves match one another as they do in the figure above.
(You can find an excellent discussion of coherence in light waves
here, last accessed on February 23, 2014)
Brain Wave Coherence. Scans of brain wavelengths and frequencies also show that brain wavelengths, like light waves, can appear more or less coherent. They too can be, "in phase," like light waves.
However, the interpretations of what this means are, from my perspective, too often linked to for-profit programs, software, or books claiming that some technique can produce higher coherence in the brain and, therefore, greater creativity or intelligence in the human mind. Since knowing more about how the brain behaves does not automatically translate into knowing more about the actions of the mind, I'd suggest you take such claims with a grain of salt.
Comprehension Checks
1. Which of the following sentences uses the word coherence correctly?
Scientists talk about the coherence of light. The term refers to light waves and the way they do or do not match each other in distance and form. Coherent sources of light produce continuous light waves of the same length or distance apart and are in synch, or in "phase," with one another.
