Just a simple argument I felt like following.There exist people who are capable of remembering their past lives. This proves that the concept of ‘I’ is one beyond the realm of the physical i.e the body.Saints and spiritualists claim the ‘I’ to be the entity called the soul.
Modern day physics establishes that there are only 2 entities that make up this universe- energy and mass. Einstein’s clichéd equation establishes that mass is also equivalent to some amount of energy; ergo, the entire universe is 1 single entity-energy. This idea of oneness is something that every established religion propounds in one form or the other. Hence, it wouldn’t be foolish to visualize the soul as a form of energy, albeit a vague and lesser known form.
The soul moves from one body to another. How could that happen? There are three ways:
Externally driven:Like a ball kept inside a car which then moves from point A to B.
Gradient driven: Like a ball on a balcony ledge rolls and falls to the ground.
Self driven: Like a ball shaped car that drives itself.
Nature works on gradients and not on agents. Potential gradients, pressure gradients and many others take care of the cosmos.
Motion from one body to another can be a process. No process in nature is inefficient. Hence, there is a chance that the soul fades away with time, each time inhabiting lesser beasts before finally becoming small enough to be significant.
It is to be noted that this argument can be easily beaten if there be an individual who can remember what he/she was, say, 500 births ago.