Final answer:
Polonius's last three lines advise Laertes to maintain integrity and self-consistency. The counsel can be straightforward or open to various interpretations, also indicating Polonius's inclination towards wisdom that favors practicality over the supernatural.
Step-by-step explanation:
The rephrasing of Polonius's last three lines before his farewell to Laertes can be interpreted as Polonius advises Laertes to be true to himself. This interpretation aligns with the original phrase 'To thine own self be true'. This piece of advice can bear multiple meanings, but the essence is that one should maintain their integrity and consistency in character in all actions and decisions. However, depending on context, there also can be a sense of ambiguity in his advice, as it may seem overly simplistic or open to various interpretations regarding what it means to be true to oneself.
Furthermore, the provided reference texts show Polonius might also caution against believing in the supernatural and imparts guidance laced with skepticism, indicating that Polonius shares wisdom on life's complexities. Through his interactions with different characters, he seems to emphasize a more grounded, practical approach to dealing with life's uncertainties and the importance of empirical evidence.