Why did George Berkeley criticize calculus in The Analyst?

In his influential work The Analyst; or, A Discourse Addressed to an Infidel Mathematician, the Irish philosopher George Berkeley criticized the foundations of calculus because he believed the methods used by Sir Isaac Newton and Gottfried Wilhelm Leibniz lacked logical justification.1

Berkeley was deeply concerned about the atheistic and deterministic implications of the philosophical mechanism prevalent at the time. He sought to expose contradictions in the use of fluxions and infinitesimals, famously describing them as the "ghosts of departed quantities" because they were neither finite nor zero.1

Beyond his mathematical critique, the work served as an ad hominem argument for religion. Berkeley challenged the intellectual consistency of mathematicians who were skeptical of religious mysteries but readily accepted the "inconceivable" points within their own science, famously stating that anyone who could accept the logic of fluxions should not be "squeamish about any point in divinity".12