Conserve and preserve, our pair for today, are an interesting twosome. And yes, I’m working my way through the massive list presented to me by that other interesting twosome, Gill and John. Thanks for all the inspiration! Anyway, you’d think that these would have specific meanings when applied to, for example, rare documents, precious items that need protecting, or ancient monuments. But in fact their specific meanings in these contexts are already encapsulated neatly into their basic, general definitions.
To conserve something is to protect it from harm or destruction or prevent it being wastefully overused. So we conserve water when we put a brick in our toilet cistern, and when we conserve a book or a building, we take steps to protect it – usually reversible steps nowadays, where someone coming along later can see what’s been done and reverse the process if they need to. This is the concept behind those glass link sections you see when an old house has a new extension added to it, or when pages of a rare manuscript are patched with a carefully inert material.
However to preserve something is to maintain in its original or existing state. No additions, however reversible. No patching. A crumbling book might be digitally photographed then kept in the dark in an acid-free box or maintained on view but in a case containing an inert gas. A house must stay the same, without patching or repairs (although sometimes like-for-like repairing is permitted, using the same materials and techniques as were originally used). Of course, it’s often difficult to know what something’s original stage actually was, whether it’s a palimpsest or a house that’s been updated over the ages – which is why “existing state” is included in the definition.
You can find more troublesome pairs here.