(a) Is it necessary to adhere to the notions of immortality of soul and rebirth in order to have a robust conception of…

(a) Soul, rebirth and the conception of liberation

In classical Indian philosophy, the necessity of an immortal soul and rebirth depends on whether liberation is conceived ontologically or phenomenologically. In Advaita Vedanta, the immortality of the soul (Atman) and its non-dual identity with Brahman is foundational; liberation (moksha) is the realization of this eternal, uncreated reality, terminating the cycle of samsara. Similarly, Nyaya-Vaisheshika posits apavarga as the complete cessation of pain, attainable only when the eternal individual soul exhausts its accumulated karma across transmigratory cycles. Early Purva-Mimamsa prioritized ritual action (dharma) to attain heavenly states (svarga), treating liberation as secondary yet sustaining post-mortem continuity.

Conversely, Buddhism deconstructs this substantialist framework through the doctrine of anatta (non-self) and anicca (impermanence). It demonstrates that a robust conception of liberation (nirvana)—the extinguishing of craving and ignorance—does not require an enduring, immortal soul, interpreting rebirth instead as a continuum of psychophysical processes via dependent origination (pratityasamutpada). Carvaka materialism rejects both immortality and rebirth entirely, dismissing transcendent liberation and identifying death (maranam eva apavargah) as the only cessation. In contemporary thought, Sri Aurobindo’s Integral Yoga reconstructs liberation not as an escape from rebirth, but as the progressive divinization of terrestrial life and consciousness, while modern naturalist ethics locates freedom in psychological integration and ethical autonomy within a single empirical lifespan.

Critically, while notions of an immortal soul and rebirth provide a coherent metaphysical scaffold for retributive cosmic justice, they are not strictly necessary. An immortal soul is not needed, as Buddhism shows. Rebirth is presupposed only if liberation is defined as release from saṃsāra; if it is defined as freedom from ignorance, craving and suffering, it can be robustly formulated as existential and psychological transformation in this life (as in the ideal of jivanmukti), without eternalist presuppositions.

(b) Spinoza's God: substance, attributes and immanence

Spinoza grounds his philosophy in substance monism, defining God as the sole, absolutely infinite, and self-caused (causa sui) substance (Deus sive Natura). By definition, substance is that which exists in itself and is conceived through itself, and God is a being absolutely infinite, a substance of infinitely many attributes (E1D6). Since no two substances can share an attribute, 'except God no substance can be or be conceived' (E1P14). God possesses infinite attributes, each expressing eternal and infinite essence, of which the human intellect perceives only two: Thought and Extension. Individual finite entities, including human minds and bodies, are not independent substances but modes—transient modifications of God’s attributes.

Critically, Spinoza’s pantheism rejects the traditional theological model of an anthropomorphic, transcendent creator operating with purpose or free will. He distinguishes between Natura naturans (God as dynamic, self-originating substance) and Natura naturata (the modal world necessarily following from divine nature). By eliminating teleology, Spinoza establishes strict metaphysical determinism: everything unfolds by geometric necessity, rendering contingency and free will human illusions born of inadequate ideas. Yet Spinoza redefines freedom: a thing is free if it acts from the necessity of its own nature (E1D7), so God alone is wholly free and humans become freer through adequate knowledge. While this brilliantly resolves Cartesian mind-body dualism through parallel attributes, it invites the critical charge of fatalism, effectively replacing personal theism with an impersonal cosmos where religious piety becomes the intellectual love of God (amor intellectualis Dei). Commentators also dispute whether the attributes are objective features of God or only ways in which the intellect perceives him, and Hegel charged the system with 'acosmism'.

(c) The problem of evil and the concept of God

The problem of evil is primarily an artifact of classical monotheism, which defines God through the rigid triad of omnipotence, omniscience, and omnibenevolence. When God is conceptualized as an all-powerful, all-knowing, and wholly good creator ex nihilo, the reality of moral and natural suffering generates the logical problem (Epicurus, Hume, Mackie) and the evidential problem (Rowe). Classical theists answer within this framework: evil as privation of good (Augustine), the free-will defence (Plantinga), soul-making (Hick) and the best possible world (Leibniz).

Where this divine framework is altered, the problem dissolves or transforms. Process theology (Alfred North Whitehead, Charles Hartshorne) avoids the dilemma by reconceptualizing God as dipolar and non-coercive, possessing persuasive rather than absolute power; evil arises from the creative freedom of worldly entities, not divine failure.

In Indian philosophy, non-theistic frameworks bypass the problem altogether. Sankhya dualism attributes suffering to the intrinsic disequilibrium of prakriti’s three gunas, leaving the pure consciousness (purusha) untouched without invoking a creator God. Buddhism locates evil and suffering squarely in avidya (ignorance) and dependent origination (pratityasamutpada), rendering theistic theodicies redundant. Even within theistic traditions, Brahmasūtra 2.1.34 answers the charge of partiality and cruelty (vaiṣamya-nairghṛṇya) by beginningless karma, and in Ramanuja's Visishtadvaita evil is explained through beginningless karma, where individual souls act as free modes within God’s organic body (sarira-sariri-bhava).

Thus the problem of evil, as a logical contradiction, is indeed a direct offshoot of the classical conception of God, and changing that conception changes the problem. Suffering itself, however, remains a practical and existential problem in every system, which each must still explain and help overcome.