Which philosopher argued against the necessity of a first cause by suggesting an infinite regress?

David Hume argued against the necessity of a first cause by suggesting the idea of infinite regress. His skepticism concerning causation and the principle of sufficient reason led him to question whether it is reasonable to assume that everything must have a cause, including the universe itself. Hume proposed that if everything requires a cause, this could lead to an infinite series of causes stretching back indefinitely, rather than a single first cause. This line of reasoning challenges traditional cosmological arguments that posit a necessary first cause or a prime mover, suggesting instead that we may not need to posit a beginning to existence.

In contrast, figures like Bertrand Russell and Immanuel Kant also challenged the idea of a first cause but did so through different philosophical lenses. Russell famously offered the concept of the universality of the universe rather than an explanation requiring a first cause, while Kant emphasized the limits of human understanding and how metaphysical concepts like causation may not apply to the universe as a whole. Voltaire's contributions were more focused on critiques of religion and dogma rather than a direct philosophical argument against the necessity of a first cause on the basis of infinite regress.