The principle causes of these unending cycles of rebirth are the inherent attitudes of attachment and aversion, and their consequences.  The attitudes of attachment and aversion, and their consequences.  The attitudes of attachment and aversion result in the bondage of good and bad Karmas and as a consequence the soul continues its passage from one dimension to the other.

Every soul is a dormant source of infinite energies, uninterrupted light of knowledge and unending joy and happiness.  Knowledge and happiness are the fundamental natural activities of the soul.  But the accumulated inertia of ignorance and illusion acts as an impediment to its endeavor to activate these inherent infinite energies.  Even when it endeavor to activate these inherent infinite energies.  Even when it launches its efforts, the dense accumulation of attitudes of attachment and aversion does not allow these efforts to become successful.  As such, the disciplining of these attitudes of attachment and aversion becomes the prime need on this path of salvation.

When its own true form is revealed on the soul it recognizes its inherent potential and gradually starts the efforts to win over the attitudes of fondness, attachment and aversion.  This continuing endeavor to root out attachment and aversion is known as the path of discipline and equanimity.  When the soul weakens the knots (Granthi) of attachment and aversion, as a result of its intense craving for salvation and practices of equanimity, penance, and meditation, it becomes tieless or Nirgranth (a term for Jain ascetic).

Continuing its un-dogmatic practices or the Nirgranth attitude, a day comes when the soul destroys all attachment and aversion and conquers fondness.  As a result of this victory the soul attains the statues of Jina.

The individual who has destroyed attachment and aversion; who is absolutely free of fondness and ignorance; who has shed the four vitiating Karmas; namely illusory (Mohaniya), knowledge obstructing (Jnanavaraniya), perception obstructing (Darshanavaraniya), and power hindering (Antaraya); is known as Vicarage (the detached one), Jina (the victorious) and Sarvajna or Kevali (the omniscient).

Any deserving soul may attain the status of Jina, omniscient, ultimate or pure soul (Param-Atma), but not a Tirthankar.  This is because of the fact that it is only as the result of a specific pious type of Karma that one may become a Tirthankar.

The lofty person, an omniscient Arihant, who defines, elaborates, and propagates Ahimsa, Truth, Brahmacharya etc., establishes the four pronged (Sadhu, Sadhvi, Shravak and Shravika) religious organization, and is endowed with unique powers is known as the Tirthankar.

It is a belief, mentioned in Jain scriptures, that it is only the soul who earns the pious bond of the Tirthankar-nam-karma through a very high level of penance and meditation, can attain the status of a Tirthankar.

During one descending cycle of time there may be innumerable omniscients but only twenty-four Tirthankars.  Acharya Somdev Suri has given an explanation about why there can only be this specific number of Tirthankars-

"If the number of things existing in nature is not a fixed figure why the numbers of things like date, day, constellations, stars, planets, oceans, mountains are believed to be fixed?  It means that although they are numerous their exact number is fixed as per the law of nature".  During one descending cycle of time only these twenty-four Tirthankars are the originators of religion, founders of religious order and persons with divine powers.

A Tirthankar is not an incarnation of the God.  He is an ordinary soul that is born as a human and attains the states of a Tirthankar as a result of intense practices of penance, equanimity and meditation.  As such, the Tirthankar is not defined as an Avatar (god-incarnate) but is the ultimate pure and developed state of the soul.  Thus he may be called as the God in human form.