Ask yourself this simple question: can science explain, or will it ever be able to explain, why you are you? This may seem silly at first, but it's actually a very important question.
When you were conceived, why did you end up your particular physical body - and not another? I don't see how science will ever be able to explain that one. Do you?
By the way, if our minds (and everything else) are nothing but matter, then what is truth? Is it matter too? If you think it is something other than matter, than you are not a strict materialist. And if you think that truth is nothing but matter, then you shouldn't care about it any more than you care about a pile of dirt, should you?