I am currently making an advertisemnt for my business that will apear in several publications where I live. I wanted two quotations on my ad (specifically Gerald Durrell and Plato - a sentence from each) and wanted to know if I was able to do this or would I need permission to put in the quotations. Thank you
Gerald Durrell is a public figure, so it's likely fine, but you can't use his image to actually sell your product or try to claim (or even hint) that Gerald Durrell endorses (or rather "endorsed" since he's dead) your business. If you think you're in a gray area there, you may want to consult a lawyer before the Durrell estate sues you. Plato is long gone and his lawyers are no longer on retainer.
What Power_Writer said. Quotes are not under copyright, so, in any situation, you can use famous people's quotes, living or dead. If you want, you can even go as far as writing a book with their quotes, and it is ok to publish it.