"Cogito Ergo Sum" when translated from Latin to English is "I think, therefore I am". The quote itself was a statement made by Rene Descartes after he conducted a search for answer for a statement he couldn't doubt. I personally find the quote to be quite true in a way. How can one know they exist without doubting the fact the world and they themselves exist. If they do doubt themselves the only way they can know they exist is by being aware and asking yourself "do you exist" or "does this really exist". For instance when dreaming sometimes the dream can be really realistic and it can be hard to know when the dream has ended so the quote would fit perfectly. Overall I think the quote is a great way to get yourself or others thinking sort of like a brain teaser and I think that's great.