In the future is a cloning device. You step in and your body and brain are cloned down to the last electron. All of your memories, scars and epigenetics are cloned here as well. Now this is key here: In all Objective sense, your clone is you. There are no distinction between you and your clone and nobody can tell who is who. You both know yourself to be you and no one would be the wiser if you went and lived in a foreign country under a different name and your clone stays back and lives your life for you. Well nobody except YOU would know. You see, to you that clone is another person that you can talk to and shake hands with. Even though a brain scan will reveal the same thought patterns between you two, you will never literally see through the clone's eyes. If the clone dies, you go on just fine, but if you die... It's over even though your perfect clone goes on. So therein lies the one distinct difference between you and your clone and that is YOUR subjective experience makes you YOU.
So the problem is is that this subjective experience has no real evidence of its existence, so it doesn't exist right? Just like fairies don't exist, right? And THAT is the absolutistic mindset of the scientific materialist.