A Preservationist is defined as a supporter or advocate of the preservation of something, especially of historic buildings and artifacts. An antiquarian is someone who studies and collects antiques or antiquities. They each have their own organizations associated with them either locally or nationally but some argue that they are different from one another for various other reasons.
Let’s compare: The main difference between the two can be documented as their intent. Antiquarians work and collect for themselves and preservationists work and preserve for others. The driving question is why. Specifically for preservation, it is argued that there are many different answers for why we preserve. They include but are not limited to Sentimentality/Emotional, to Accommodate future research, Maintain historical integrity, Repair not Replace, Culture v. History and Economic reasons. While antiquarians aimed to save antiques that kept the culture of their nation. In 1707, the Society of Antiquarians of London was founded. It claimed to be a revival of the Elizabethan Society of 1585 and focused on English archaeological remains.
From what I have read and understand I would say that they are not exactly the same but are variations of one another. Each group seeks out treasures of the past that are worth keeping and worth collecting. This fact alone is enough to make them sister professions/fields.It is said that antiquarians collect for themselves and preservationists for others but we see a cohesive combination of the two in a very common form,
In Giving Preservation A History, we learn that preservation lands beyond just buildings but stretches to monuments and museums. A museum is where antiquarians finds go for everyone, not just for themselves. and it breaks the preservationist myth that something does not have meaning unless it is still located where the event happened that made it significant. Basically the driving force between the similarities and differences of the two is why. Why we preserve and why we collect antiques.