You’ve seen her in every historical adventure or fantasy film you’ve ever watched: The plucky female character who wears pants, refuses to get married, and shares her outspoken opinions about suffrage, slavery, and so on with anyone who will listen. She is the anachronistic character.
An anachronistic character is someone in a historical-inspired work whose attitudes and opinions would be wildly out of place within the setting, but would fit right in today. Women from the Victorian era or the middle ages who have modern feminist opinions are the most common example, but it can also include progressive attitudes about race, politics, and social structure (for instance, a character in a feudal culture advocating capitalist democracy). Beginning writers often write anachronistic characters because they’re worried that readers will mistake their characters’ attitudes for their own; for instance, not wanting to make a character in early 20th century America racist for fear of seeming racist themselves.
Now, not every character who disagrees with social norms is anachronistic, nor is every character whose attitudes would fit in today. Every era has had its reformers and dissidents; American abolitionism, for instance, are as old as American slavery itself. And sometimes attitudes only seem anachronistic because of modern misconceptions, like the idea that every premodern culture was as prudish about sex as the Victorians.
The key point is not just that the character’s attitudes are unusual for the day and age, but that they’re specifically chosen to appeal to modern sensibilities. For instance, a lot of female characters decide to defy conventions and wear pants, whereas male characters never defy conventions and wear dresses, even in settings where both would be considered equally deviant.
Another important aspect is the scope and connotations of the opinions. Anachronistic characters act with the aggressive confidence of someone who knows for a fact that their opinions will be validated in the future. They happily reject values and principles that would have been considered foundational in their culture and instead use modern reasoning to support their positions. Sometimes they end up sparking full-fledged social movements and changing the whole culture. Needless to say, these movements always succeed.
In real life, there have always been people who didn’t fit well into their prescribed social roles, both in real life and in fiction, from Jo March to Scout. But these characters are also products of their culture and they interpret their experiences in that light. They know full well when something is unfair, but they don’t necessarily conclude that their whole culture is at fault, and they usually respond within culturally acceptable bounds. This doesn’t make them weak or oppressed by their culture; people today obey similar social boundaries. That’s why not many men wear dresses.
The solution to the anachronistic character, then, is not simply to go the other direction and make every character in the story unthinkingly accepting of the status quo. This is unrealistic in its own way, and things like racism were wrong and ugly even in contexts where they were widely accepted. Your characters can and should be critical of their culture at times, but they must do so from within that same cultural context, taking into account all the attitudes and beliefs that inform it, and with a realistic understanding of what they can accomplish. Don’t just make them sound like time travelers from 2016.
First image is from Sherlock Holmes (2009). Second image is from King Arthur (2004). Third image is from Mulan 2.