Presentism

Presentism can refer to either a style of argumentation or philosophical position, depending on the context in which it's used.

In history and sociology, presentism describes when the ideas of the present unduly inform perspectives on the events of the past. The use of the word is pejorative.

In philosophy, presentism is the belief that only the present exists.

Historical determinism and context
In the field of history and sometimes sociology, presentism is a style of writing or argument that can be fallacious, depending on the circumstances. Most simply, presentism refers to, intentionally or unintentionally, writing history from a teleological point of view (or historical determinism) or reading primary documents outside of their historical context. The most blatant forms of presentism are revisionist, negationist, or triumphalist histories attempting to justify the actions of a certain group or paint it as superior. Teleological forms of history like that of Karl Marx or technological determinism (the belief that technology determines history) and triumphalist pseudohistories like those written by David Barton are usually characterized as presentist. Those extolling the good old days or a golden age inevitably commit this fallacy.

Moral judgments
Another common form of presentism is allowing present-day moral judgments to creep into characterizations of the historical figures. For example, you can dig up quotes from any number of figures active in civil liberties or equal rights movements that would seem racist, sexist, or otherwise bigoted by today's standards to paint them as crazy, reactionary wingnuts. Historians remind us that people are products of their times and so must be judged within that paradigm (though what establishes the moral mandate that they must be judged on such terms isn't exactly clear). It is probably more accurate to say that historians are primarily interested in simply describing the events of history as accurately as possible, and providing moral judgements in one's presentation arguably distorts this aim. This is similar in part to the aim of antrhopologists who espouse a professional cultural relativism.

Some, especially politicians, are often blamed for consequences of their actions that they could not have foreseen. This often boils down to legal-esque argument over whether the individual was negligent, short-sighted, or acting with malicious intent. In good scholarly historical work, like in law, it's imperative to separate the consequences of the action from the intent.

Similar criticism is levelled at fictional works made and/or set in bygone eras, such as with the Brothers Grimm fairy tale "Snow White" especially with the better-known Disney version where Prince Florian is seen in the finale kissing Snow White. Folks have argued that the "true love's kiss" is non-consensual, and whatever resuscitation attempt Prince Florian could done to the girl would amount to rape. Criticizing the creators for knowingly depicting rape as a positive thing can be called presentist; that being said that doesn’t mean we must therefore consume such media in the modern day uncritically. Doing so may allow the spread of harmful messages in the present period. There is a reason many people don’t simply watch The Birth of a Nation as if it is just another film, even if at the time of release it wasn’t viewed as problematic.

The historian's fallacy
The term "historian's fallacy" is sometimes used synonymously with presentism or considered to be a type of presentism. The term was coined by David Hackett Fischer to refer to characterizing the actions or decisions of historical figures as if they had access to all the information we have now in the present. Thus, it is similar to the problem with moral judgments as above. These could be considered a form of outcome or hindsight bias. This is more commonly known among historians as anachronism.

Whig history
views the past as a march of progress towards the present age of liberty and enlightenment. Assuming that current political ideas were in fact held in the minds of prior figures, it cast those figures in the roles of heroes, people who laid foundations for the current status quo, or villains who opposed them. Whig history frequently appears in the historiography of science, especially in popular works of the Microbe Hunters type. Scientists were either heroes, who are on the side of truth (as is now known), or villains who opposed the emergence of these truths because of ignorance, bias, or clinging to power.

Chronological snobbery
C.S. Lewis coined the term "chronological snobbery" for a similar phenomenon in which intellectual accomplishments of the past are considered necessarily inferior to the ones of the present. This could be considered a type of appeal to novelty.

History itself as a historical product
Less commonly, presentism is sometimes used to refer to works of history themselves as products of their time. There is some debate between historians over what degree historical works are simply products of their time and if, in fact, this is inevitable. Thus, presentism is often unintentional as well as intentional.

Not fallacious
Of course, if you're marshaling historical fact to make an argument about the present, presentism is not fallacious. For example, making an argument for a certain policy based on history is obviously not a fallacy, but is not usually labelled as "presentism" as it's considered within the purview of political science or political philosophy rather than history, though the lines can often be blurry.

Criticism
A criticism that is often held against the historian's claims of presentism when applying moral judgements is that it admits a type of moral relativism. Philosophers who espouse objective morality argue that whether or not a given act is morally acceptable or unacceptable is timeless, so it does not constitute a genuine cultural bias when moral judgements are made of historical figures. There is also the question of how far back or what constitute cultural relevancy when speaking to deeds of those in the past. At what point is something far enough in the past as for "present" moral judgements to no longer apply?

Religious figures also object to the claims of presentist bias on the grounds that morality is a eternal standard established by God, and so cannot vary throughout time. To say this is debatable is putting it lightly.

Philosophy
In the philosophy of time, presentism is contrasted with eternalism. Presentism is the metaphysical view that only the present moment actually exists, while eternalism holds that all events in time are equally existent. This is unrelated to the concept of "presentism" used by historians.