Final answer:
The philosophy mentioned is from the play 'Twelfth Night' by William Shakespeare and is expressed by Sir Toby Belch.
Step-by-step explanation:
The philosophy stated in the question is not attributed to any of the characters mentioned. It is a quote from the play 'Twelfth Night' written by William Shakespeare. The character who expresses this philosophy is Sir Toby Belch, who tells Sir Andrew Aguecheek that a woman should always choose an older man because men change their minds more often than women.
Learn more about Philosophy of relationships in 'Twelfth Night'