First of all, if we say our value is purely subjectively us giving ourselves value, then if someone values us less, and we value ourselves more, what is our true value? If we decide we are the most important person in the world, do we automatically become the most important person in the world?
Do we set our value so if I want to make myself so great in my eyes, then automatically I can do this?
Obviously, we have don't simply assign value to ourselves, but when we judge, we do so with some sort of guesstimate at our true value. We all believe there is a measurement to who we are.
...and that they may know their Lord encompasses everything in number. (Quran)
Our value whatever it is, is not maintained by our perceptions. But we know it requires perception. As it requires perception, there has to be an objective perception who maintains that value.
How do we see it? We can see that we aren't made of some sort of unique value that is totally different then a value in another being, like one human is of totally different type x value and another human being is of y value, and x and y have nothing really in common. There is something binding us. There is something in all this. That something, in the words of Imam Ali, is expressed:
"He is in all things without being merged in them neither separate from them"
The different hues of value, the different forms, the different relationships established through it, are all manifestations of a greater value, a link to something greater, an absolute source and basis, an eternal reality.
As objective value cannot be arbitrary, it follows it's eternal and not something God can create out of nothing. Rather he creates through the truth of vision of himself for witnesses all things in himself.
Naturally we can all see this. That for example, there is something extra special about love. When we value a person to the degree we love them, we are bonding with "value" and valuing in a special way, that transcends and points to something special.
These signs of value, from honor, to courage, to compassion, to affection, are all signs of something greater. Something that these things are emerging from, but are depending to manifest.
That in thing lives inside of us "he is all things..."but he isn't merged into us neither is he separate from us.
The signs point in a way, in which they link to perfection, to one essence, that unites them all in a single absolute reality. They point to transcendence that doesn't lack a single possible existence or praise or beauty or glory or greatness or anything to be valued. The Ultimate Value by which all value emerges from.
This is one of the reflections of Quran "Or are they created from nothing...", contrary to what people might think, this verse is clearly not saying that anyone believes nothing existed and then creation emerged from that. Some humans believe that universe was eternal, however this verse is addressing the polytheists, do they think their essence is created from nothing, their souls are just created by God from nothing. Rather, he created it from water of his own light, his own value, and created through his name/face/light.
Now this explanation of the name of God/face of God the true reality of the human being, how can we know it to be true? This takes sincere reflection upon which we realize that value is not something we simply make up or biological brain assigns and maintains.
Aside from this is how our positive or negative actions play a role in our value. As said before, we don't simply decide we are the best people on earth, and hence become the best person on earth.
There is a value to who we are. When do actions, we inherit it. Our value is actually increased or decreased. We don't decide the degree of that measurement. Sure we may think of ourselves at that moment and have our over all judgement of ourselves, but we all realize if Hitler thinks he is righteous it doesn't make him what he values of himself automatically the true value of himself. His actions degrade him, they put on the negative scale, in - side of zero, not on the positive.
There is something making us inherit our actions, a judge that perceives who we are, because this qualitive type measurement can only be maintained by quality type perception.
It's not like a rock, it has weight, but it doesn't matter if we measure it or not, this is qualitive, in which it depends on perception of who we are and maintaining that and making us inherit our actions.
And so these type of reminders, that we do believe that there is some sort living record to who we are, that it forms the true nature of value of ourselves, even if we underestimate or overestimate ourselves, there is an objective value.
We know these to be true, and would not be able to subjectively value ourselves without belief there is an objective value.
We see these signs in ourselves and in the horizons, pointing to something Greater. Something in which is the source of all it and unites all possible levels of value.
The only way to measure it is to gain vision from the vision of the Creator, the closer it is to the vision of the absolute, the closer it is to making right judgement.
However we all been given a degree of that judgement or would not be able to condemn the likes of Saddam or praise the likes of Mandela.
When we do good acts we are in a state, there is beauty to it if good, we inherit that beauty. The truth is there infinite beauties, but there is beauty that unites all beauty, and there is souls that are upon that united beauty. It's they who manifest God the most, reminding us of God's unity thereby. But we can never grasp their value in that way God values them, because only God can see himself.
Imam Ja`far as-Sadiq (as) said: "Surely, we have revealed it on the Night of value." (97:1) The night is Fatima al-Zahra, and the Value is God. Whoever recognizes Fatima in her rightful manner will have comprehended the Night of Value. She was named Fatima because the Creation has been prevented (fatamu) from recognizing her [fully]."