A breakdown of Walter Benjamin's "The Work of Art in the Age of Mechanical Reproduction," explaining concepts such as expressive authenticity, cult value, and the aura.

Walter Benjamin's concept of the aura of the authentic is one of the key ideas when it comes to issues of authenticity. Benjamin developed this concept in his most celebrated essay "The Work of Art in the Age of Mechanical Reproduction".
Authenticity
Encompasses two distinct dimensions.
Aura
Mechanical Reproduction
Now let's break down Benjamin's essay.

The term authenticity may be used to describe two separate things: nominal and expressive authenticity.
Benjamin mostly refers to nominal authenticity in his essay, although he brings up issues addressing both.
Expressive authenticity refers to the ability to be faithful in ones own self, to express genuine qualities and possess inherent and self originating authority.
This authenticity is the one that Hegel, Heidegger and many existential philosophers have much struggled to define and understand.
Nominal authenticity stands on the other side of forgery and fakery. It is related to the provenance of an object, ie., its unique path through time and space. As such, this authenticity is particularly relevant to works of art.

Benjamin's position is that every original has an element which no reproduction can ever capture, no matter how faithfully it copies the original image.
This element is the aura, is the original's unique presence in time and space. It entails the visible marks left by the passage of time and the history of which the object has been subjected to throughout its existence.
These qualities can be retrieved with scientific methods and would never be found on any reproduction.
Example: The Mona Lisa dates to 1503, and no reproduction can ever replicate that.
Because of this exclusive characteristic of the original, Benjamin claims that
"the whole sphere of authenticity is outside technical- and, of course not only technical- reproducibility."

Manual reproduction (forgery) has always allowed the original to retain its authority as it heavily depends on the original's qualities and existence.
Mechanical reproduction is largely independent from the original.

Mechanical reproduction degrades the original's authority because the copy can become something that the original would never be.
Example: the photo of a cathedral can become part of a personal collection, the sound of its choir can be heard in open air or in a drawing room etc.
Benjamin clarifies that mechanical reproduction does not usually alter the physical presence of the original but almost always depreciates the quality of its presence.
Essentially, mechanical reproduction harms the authenticity of the art object contesting its authority on transmitting meaning. As the historical testimony of an object is also based on its authenticity, the former is too jeopardised.
Benjamin expresses with the term "aura" the element of the authentic that suffers. He then proceeds to his main argument that:
"that which withers in the age of mechanical reproduction is the aura of the work of art".
But why? Benjamin is clear:
"by making many reproductions it [mechanical reproduction] substitutes a plurality of copies for a unique experience".
Mechanical reproduction also takes the object out of its context and essentially shatters the tradition it embodies.
Example: In photography, there is no reason to look for the original (the negatives) because its purpose is to serve as the matrix for a series of identical copies. This means that modernity has practically eliminated authenticity, by making the original work of art, which is the prerequisite of authenticity, completely irrelevant.
Another important idea is that of art based on ritual as opposed to art based on politics.
Art based on rituals
Art based on politics

Benjamin distinguishes between two ways of valuing art. The first is based on the cult value of an artwork and the second on its exhibition value.
Cult value
When art was part of rituals, says Benjamin, its cult value was of extreme importance.
Decorated pottery laid buried in graves, paintings hidden in temples were accessible only to priests, and statues carefully concealed were only unveiled on special occasions.
Exhibition value
With modernity the cult value of art is now second to its exhibition value. Art is now created to be exhibited as widely as possible.
Frescoes in christian temples had a limited exhibit value as only travellers could witness them. Stage actors were seen only by those lucky enough to pay a ticket to access the theatre. Today a photograph can travel wherever needed and cinema can make the performance of the film actor accessible to audiences all over the world.
Long story short, the exhibit value today has overshadowed the cult value of art. This emphasis on exhibiting has led to an accessible art that is exposed to criticism. In contrast, cult art could not bear criticism which diminished its authority and function.

Returning to the concept of authenticity, I would like to present an alternative to Benjamin's. Disagreeing with Benjamin, Cornelius Holtorf (2013) has claimed that authenticity is a quality of a historical object that can be easily reproduced in the present.
Holtorf's understanding of authenticity focuses on historical objects and the way we experience authenticity threw an object's 'pastness'.
"Pastness is the result of a particular perception or experience. It derives from, among others, material clues indicating wear and tear, decay, and disintegration" Holtorf 2013, 427.
The idea is simple, if something looks and feels old, we will mistake it for authentic. So in this sense, it's rather easy to manufacture "authentic" experiences as well as "authentic" objects. Authenticity in this sense is not a metaphysical, inherrent quality of an object but a phenomenologicaly reproducible aspect.
This is something that the elites of the Early Modern Era understood very well, and it's the basis behind all the invented traditions that Eric Hobsbawm exposed with his monumental work Invented Tradition (1983).
Benjamin's essay explores multiple issues such as the evolving reactions of the masses against art, Dadaism, and most importantly the concept of the optical unconscious.
Benjamin's The Work of Art in the Age of Mechanical Reproduction may not be perfect and certainly has problematic aspects such as the idea that art is no longer experienced as part of rituals, which is certainly incorrect.
Nevertheless, Benjamin's essay remains a central text in understanding authenticity; a point of reference whose ideas are often contested and discussed.