Difference between soul and R&B

Although these two are very similar, i feel like there is one distinct difference. When you hear a soul or R&B song, they usually both sing the same tune. But the main difference to me is that the artists who sang soul more than likely actually experienced the problems that they were singing, as to R&B the artist is most likely trying to sell a record. Also, i think soul was probably more popular back then because the problems the artist was experiencing were more than likely the same problems the audience were experiencing, so they could relate more, hence the music was probably more popular.