Let’s explore a scientific answer to your question of why each one of us is unique, and hence none of us match with each other.

Each one of us is standing at a different point, at a given point of time, on the path of evolution, based on our development. Hence, this results in making us very much unique.

The natural flow of progression of an embodied Soul in this world
We all travel on our evolutionary journey differently. Let’s see how...

The Soul is what we really are. But every Soul begins its evolutionary journey from a stage where it is totally covered by the coverings of karma. A living being, when in this stage, is called Nigod. This is where the Soul is in a dormant stage i.e. not a single ray of light of knowledge of the Soul is coming out as it is totally covered with karmic atoms.

When one Soul is liberated from the world, meaning gets completely free from every covering of karma, one Soul from Nigod enters this world.

For this to happen, a little covering from over the Soul of the Nigod gets removed, wherefrom little light of Soul comes out; and thus one sense is developed. With this, the particular living being begins its journey in this world. When a Soul enters this world, the living being attains a name and form.

Thereafter, the living being gradually develops from one-sensed to a two-sensed living being, then to a three-sensed living being, a four-sensed living being, a five-sensed living being, and only then it comes into human life-form where his mind, intellect, ego gets developed.
As coverings keep reducing, development happens. Up to human form, it is natural development (based on Darwin's theory of evolution). Thereafter, anger, pride, deceit, and greed develop in the human form. That too is a part of development only. With anger, pride, deceit and greed, the human being binds new karmas.

This is how we all are at a different stage of our own respective development. For example, a person at a particular mile of development may intend to indulge in the karma of stealing as he finds in it a way to attain happiness quickly and effectively. However, another person who’s standing at an advanced mile of development, has surpassed this mile, and on learning from the experience he has accumulated so far, in various lifes, he now views stealing as a bad deed. Therefore, he shall never steal, even when he finds a fortune in a situation where no one is seeing him.

And when the other living being comes to this advanced stage of development (the same space), the time factor has changed. Hence, each and every person is unique and not matching. One’s body, one’s looks, one’s nature, one’s anger, pride, deceit, greed, attachment, ego are all a result of the karmas one binds, based on his level of development.

On the path of development then, one’s anger, pride, deceit and greed increase to a very great height. One has enormous attachment, anger, greed, pride, a lot of fights, a lot of suffering. That is when one wishes to get liberated.
Ultimately, when one gets Self-Realization, the worldly development completes there. New karmas stop being charged then. So, when one attains Self-Realization, he is liberated from the bondage of new karma. And when discharge of all old karmas finishes, one attains liberation. The Soul gets totally liberated!

This is a natural development process for every Soul,
that begins from a total dormant stage where there is no knowledge or no vision at all, and
then develops from one-sensed to five-sensed living being and evolves upto human form, and
finally attains liberation.

But whilst all of this is going on, the Soul of each is Uniform
There are six eternal elements in this world namely Soul, matter, time, space, the element that induces motion, and the element that stations. Every element is everlasting and uniform in nature (in terms of their inherent properties).
When the elements revolve around each other, the phases of the element occur. What we can see are only these phases. Just like the Sun, Moon and Earth revolve around each other, and phases of the Moon is what we can see. Human beings, animals, insects are all phases of the Soul. And it is these phases that are not matching due to different karmas, as explained above.

To know more: https://www.dadabhagwan.org/path-to-happiness/spiritual-science/the-scie...

Author's Bio: 

Ambalal M. Patel was a civil contractor by profession. In June 1958, spontaneous Self-Realization occurred within Ambalal M. Patel. From this point on, Ambalal became a Gnani Purush, and the Lord that manifest within him became known as Dada Bhagwan. A Gnani Purush is One who has realized the Self and is able help others do the same. Param Pujya Dada Bhagwan used to go from town to town and country-to-country to give satsang (spiritual discourse) and impart the knowledge of the Self, as well as knowledge of harmonious worldly interactions to everyone who came to meet him. This spiritual science, known as Akram Vignan, is the step-less path to Self-realization.