The wise old man (also called senex, sage or sophos) is an archetype as described by Carl Jung, as well as a classic literary figure, and may be seen as a stock character. The wise old man can be a profound philosopher distinguished for wisdom and sound judgment.
This type of character is typically represented as a kind and wise, older father-type figure who uses personal knowledge of people and the world to help tell stories and offer guidance that, in a mystical way, may impress upon his audience a sense of who they are and who they might become, thereby acting as a mentor. He may occasionally appear as an absent-minded professor, appearing absent-minded due to a predilection for contemplative pursuits.
The wise old man is often seen to be in some way "foreign", that is, from a different culture, nation, or occasionally, even a different time, from those he advises. In extreme cases, he may be a liminal being, such as Merlin, who was only half human.
In medieval chivalric romance and modern fantasy literature, he is often presented as a wizard. He can also or instead be featured as a hermit. This character type often explained to the knights or heroes--particularly those searching for the Holy Grail--the significance of their encounters.
In storytelling, the character of the wise old man is commonly killed or in some other way removed for a time, in order to allow the hero to develop on his/her own.
In Jungian analytical psychology, senex is the specific term used in association with this archetype. In ancient Rome, the title of Senex (Latin for old man) was only awarded to elderly men with families who had good standing in their village. Examples of the senex archetype in a positive form include the wise old man or wizard. The senex may also appear in a negative form as a devouring father (e.g. Uranus, Cronus) or a doddering fool.
In the individuation process, the archetype of the Wise old man was late to emerge, and seen as an indication of the Self. 'If an individual has wrestled seriously enough and long enough with the anima (or animus) problem...the unconscious again changes its dominant character and appears in a new symbolic form...as a masculine initiator and guardian (an Indian guru), a wise old man, a spirit of nature, and so forth'.
In fiction, a wise old man is often presented in the form of a wizard or other magician in medieval chivalric romance and modern fantasy literature and films, in the style of Merlin. Notable examples include Gandalf from The Lord of the Rings and Albus Dumbledore from Harry Potter.
Around the 1850s, the antiquarian Robert Reid used the pseudonym "Senex" when contributing articles on local history in the Glasgow Herald. These were later published in a series of volumes. Sir Alan Lascelles used the pen-name "Senex" when writing to The Times in 1950 setting out the so-called Lascelles Principles concerning the monarch's right to refuse a prime minister's request for a general election.