the reason is the guiding principle of the mind in the process of thinking. Freq. contrasted with will, imagination, passion, etc. Often personified.
this is one of The Oxford English Dictionary definitions for the word reason.
I don't get the last part. whats the meaning of personified? I searched a lot and it was written that personified meaning is "represent (a quality or concept) by a figure in human form". but doesn't make any sense. is reason not a aspect of being human?