Van Fraassen defends constructive empiricism: science aims for empirical adequacy—not literal truth about unobservables—challenging scientific realism and the 'no miracles' argument. He distinguishes trusting instruments from believing theories, affirms common-sense realism about everyday objects, and argues determinism and causation are features of models, not reality itself. Drawing on Kierkegaard and Sartre, he frames free will as an inescapable existential commitment grounded in rational self-consciousness, not metaphysical indeterminism. Rejecting the self as a 'thing', he draws on Wittgenstein and Calvino to show agency persists without ontological reification. Critiquing analytic metaphysics as linguistically confounded and often vacuous, he embraces a religious existentialism—affirming God through lived faith, liturgical practice, and narrative, not argument or doctrine. His Catholic conversion emerged from receptivity and continuity, not proof, embodying a stance where logic, humility, and devotion coexist without reduction.