Reliable researching back from the beginning of the 18th century is problematic for most people. "Ordinary" folk were not the subject of sufficiently detailed official records to allow for the cross-checking from one documentary source to another which is necessary if research is to be more than (educated) guesswork. A very unusual name, particularly if you are researching a small, tight knit community, may allow one to decide that the odds are against there being more than one possibility. By and large, the only early documents that one can confidently rely on to provide the same degree of certainty as one gets with the marriage cert/birth cert/census combination are wills. So your chances of progress depend very much on the economic situation of your ancestors.
Professional researchers can offer good advice on the sort of records which may help in your quest and have easier access to sources which are not available online, CD or LDS film. A good researcher will help you evaluate the information they find. One who purports to be able to provide a definitive answer is probably best steered clear of.