How does Popper characterize scientific progress? According to him, one finds in the history of science invariable transitions from theories to better theories. What does the word, “better” stand for? It may be recalled that, according to Popper, no scientific theory however corroborated can be said to be “true”. Hence, Popper drops the very concept of “Truth” and replaces it by the concept of “Verisimilitude” (truth-likeness or truth-nearness) in his characterization of the goal of science. In other words, though science cannot attain truth, that is, though our theories can never be said to be true, science can set for itself the goal of achieving higher and higher degrees of Verisimilitude, that is, they can progressively approximate to Truth. So, in science, we go from theory to better theory and the criterion of betterness is Verisimilitude. But, what is the criterion of Verisimilitude? The totality of the best implications of hypothesis constitutes, what Popper calls, the empirical content of the hypotheses. The totality of the test implications, which is borne out, constitutes the truth content of the hypothesis, and the totality of the test implications, which is not borne out, is called the false content of the hypothesis. The criterion of the Verisimilitude of a theory is nothing but truth content minus the falsity content of a theory. In the actual history of science, we always find the theories being replaced by better theories, that is, theories with higher Verisimilitude. In other words, of the two successive theories, at any time in the history of science, we find the successor theory possesses greater Verisimilitude and is therefore better than its predecessor. Indeed, according to Popper, theory is rejected as false only if we have an alternative which is better than the one at hand in the sense that it has more test implications and a creator number of its test implications are already borne out. The growth of science is convergent in the sense that the successful part of the old theory is retained in the successor theory, with the result the old theory becomes a limiting case of the new one. The growth of science thus shows a continuity. In other words, it is the convergence of the old theory into the new one that provides continuity in the growth of science. It must also be mentioned in this connection that unlike inductivists or positivists, Popper is a realist in the sense, according to him, scientific theories are about an unobservable world. This implies that the real world of unobservables though can never be captured by our theories entirely is becoming more and more available to us. Popper contends that the greater and greater Verisimilitude attained by our theories evidence that the gap between the Truth and our theories can never be completely filled, it can be progressively reduced, with the result the real world of unobservables will be more and more like what our theories say though not completely so.