Plastic surgery is vain and unwise, (and) thus it should be banned.
We can use the word "and" with adverb like "thus" as shown above.
But why is it impossible do the same thing with word like "furthermore" when they are same adverb? For example, in this case.
People say that plastic surgery is vain, furthermore they also assert
that they should ban it.
Like this, if I use "and" with "furthermore", whole sentence becomes so wrong. Why is that?
Best Answer
Most style guides would advise against both your sentences without the and. It's a comma splice. Since you are connecting two independent sentences. It's a common mistake and ELU has it's own tag (with 50 questions) for it. Have a look at this blog to see about possibilities to resolve comma splices.
As pointed out in several comments, both words are conjunctive adverbs and cannot connect those sentences on their own. Just have a look at this ugly site from a university professor.
Therefore, the question is not simply the combination of the two words but the grammatical construction of joining two independent sentences. And is a coordinating conjunction which is per previous blog a reasonable way to resolve a comma splice. This is exactly what you have done in the first sentence by adding the and.
Grammatically there is nothing to indicate that doesn't work for your second sentence.
However you are right that and thus is significantly more common than and furthermore, which might have prompted your question. On the other hand, it's hardly unheard of. Just a few examples:
Dame Judi Dench even titled her memoirs And furthermore