The main body of writings from Marcus Aurelius is The Meditations.
I read The Meditations very carefully when preparing to write my 2005 book, Marcus Aurelius: The Dialogues (Shepheard-Walwyn). I certainly cannot recall having read this particular quote by Aurelius.
[Mod note: Having answered the question above, the following is speculation by an expert in the field, which may cast more light on the origins of the misquote.]
I did however have MA in my book engage in a fictional debate re the classic question: If evil falls upon the innocent, how can the gods be just? In my book, MA considers each of the standard logical answers to the question:
- They are not just;
- They are unaware of the evils that befall upon the innocent;
- They are aware but powerless to intervene;
- The gods don't exist.
BTW: I have MA dismiss each of the above answers.
With all due modesty on my part, I wonder if the above quote may possibly have been triggered by this particular section of my book.
Could I imagine MA making such a quote?
Yes, in part, I could. Certainly, he was doubtful whether the after-life existed but was convinced that whether it did or not was irrelevant to how we should choose to behave in this life.
That said, he disdained the concept of living with the object of achieving honour in the minds of posterity.
Hence, I am dubious he would have said "If there are no gods, then you will be gone, but will have lived a noble life that will live on in the memories of your loved ones".
I believe that MA's key message for himself (and now, as it happened accidentally, for us) was that to achieve peace of mind (the spirit at rest with itself) then we should engage with life in a virtous, charitable and kindly manner: That the peace of mind we thereby earn is sufficient reward in itself; we neither need - nor deserve more.