A New Look at Potential vs. Actual Infinity

The {\it technique} of classical mathematics involves only potential infinity, i.e. infinity is understood only as a limit, and, as a rule, legitimacy of every limit is thoroughly investigated. However, {\it the basis} of classical mathematics does involve actual infinity: the infinite ring of integers $Z$ is the starting point for constructing infinite sets with different cardinalities, and, even in standard textbooks on classical mathematics, it is not even posed a problem whether $Z$ can be treated as a limit of finite sets. On the other hand, finite mathematics starts from the ring $R_p=(0,1,...p-1)$ (where all operations are modulo $p$) and the theory deals only with a finite number of elements. We give a direct proof that $Z$ can be treated as a limit of $R_p$ when $p\to\infty$, and the proof does not involve actual infinity. Then we explain that, as a consequence, finite mathematics is more fundamental than classical one