The passive voice is a way of talking about something without thinking too hard about how it happened.
No, no, no. Put down your grammar books. Set them on fire if you want. We won’t be diagramming sentences today. What you need to know about the passive voice is how it can affect the details you notice. I’ll show you what I mean. Here is a short story in the passive voice:
The vase was broken by the cow.
When you read that sentence, what do you see in your mind? The first thing you imagine is a broken vase, right? It’s only after you picture the vase that you see the cow. She’s an afterthought. The fact that she’s the one who broke the vase is not very important.
Here’s the same story about the cow and the vase, but this time it’s in the active voice:
The cow broke the vase.
See the difference? Now you picture the cow breaking the vase. You can’t separate the cow and the broken vase (the cause and the effect) the way you could in the passive version. In fact, in the passive one, you could get away with not mentioning the cow at all — the vase was broken, period — and then you’d never know who did it.
There are other ways to use the passive voice, but this one is the most insidious. It lets the person speaking separate what happened from how it happened, and sometimes leave out the “how” altogether. That’s what people are doing when they say “mistakes were made” — they want you to think no one is responsible.
Remember: Mistakes do not make themselves. Ask more questions.