Answer

In Jain Dharma:

• All Tirthankars ultimately become Siddha after attaining nirvana.
• A Tirthankar is Arihant while living after attaining Keval Gyan.
• After leaving the body, that same Tirthankar becomes Siddha.

So, among the 24 Tirthankars of the present time-cycle:

• All 24 Tirthankars are now Siddha, because all have attained moksha.
• When they were living after Keval Gyan, they were Arihant Bhagwan.

Explanation

The difference is:

• Arihant: A soul that has destroyed the four ghati karmas, attained Keval Gyan, and is still living in the body.
• Siddha: A liberated soul that has destroyed all karmas, left the body, and reached Siddhashila.

For example:

• Bhagwan Mahavir, after attaining Keval Gyan, was Arihant Bhagwan.
• After attaining nirvana at Pavapuri, Bhagwan Mahavir became Siddha Bhagwan.

Spiritual Understanding

Arihant and Siddha are both worshipped in the Navkar Mantra:

• Namo Arihantanam — bowing to Arihants
• Namo Siddhanam — bowing to Siddhas

Arihants show the path of liberation while present in the world. Siddhas represent the final state of pure, liberated soul.

Takeaway

All 24 Tirthankars were Arihant while living after Keval Gyan, and all 24 are now Siddha after attaining moksha.