Mona Lisa’s sister

The year is 1504, the place Florence, Italy, and Leonardo da
Vinci has just completed his greatest masterpiece, the Mona Lisa.
He decides to take a break from art and, being a bit of an allround
polymath-cum-jack of all trades, he decides to devote some time to his other great love, inventing. After many weeks of
contemplation, and long nights of ever more detailed sketches, he
finishes the plans for his cleverest contraption yet: a time machine.
After many more weeks locked away in his workshop he finally
completes it late one evening, and goes to bed that night feeling
rather uneasy as he ponders how to test it out.
The next morning his unease is vindicated when he finds to
his astonishment a painting in the time machine. It is a portrait of a
woman who bears a close resemblance to his Mona Lisa: the same
facial features and long dark hair, but without the enigmatic smile.
He immediately recognizes the woman as Mona Lisa’s ugly sister,
Mona Lot, who had been pestering him to paint her and whom he
had been avoiding for some time. This painting is clearly his own
work (it even has his signature) and, since he knows he has not
painted it, he deduces that it must have been sent back in time from
a future Leonardo. Of course he is thrilled by this. He decides not
to tell anyone but to keep the new painting under wraps while he
figures out what to do.
As the days go by Leonardo becomes more and more worried
about possible time travel paradoxes. He knows he must send it
back because that is how it came into his possession. On the other
hand, if and when he does he loses it forever. It will be stuck in a
time loop.
There are two different paradoxes here. The first is a no choice
paradox since Leonardo knows he must at some time send the
Mona Lot back in his time machine. Let us suppose there was a
note with the painting specifying the time and date it was sent.
He knows as he approaches that day that whatever he may try to
do to avoid sending it back he will fail. What if he tries to cheat
time by destroying the painting? This a very severe form of the no
choice paradox. We have no problem with our inability to alter the
past and use phrases such as ‘it’s no use crying over spilt milk’, and
‘what’s done is done’. Here though, the future is linked directly
to the fixed past and is itself therefore fixed. So what is it that will
stop Leonardo from destroying the Mona Lot? What unknown
force will protect it from being burnt, slashed or thrown into the
river Arno?There is another kind of paradox which to many is even more
disturbing than the no choice paradox and which I will refer to as
the ‘something-from-nothing’ paradox. It arises even if Leonardo
does send the painting back at the allotted time, and then destroys
the time machine before it can give him any more headaches.
We are still left with a puzzle, namely who created the Mona Lot?
Leonardo may now feel that he has weathered the storm and that,
whatever strange obstacles there may have been to thwart his
possible attempts to force a paradox, the whole episode is now
thankfully in his past. But there is no getting away from the fact
that, for a while, there existed a Leonardo da Vinci masterpiece
which at no time did Leonardo da Vinci actually paint! He found it
in his time machine, kept it for a while before putting it back into
the time machine and sending it back to himself. But where did it
originally come from? Apparently nowhere. It was caught in a time
loop and Leonardo never painted it! No amount of arguing about
ensuring logical consistency can lay the something-from-nothing
paradox to rest.