The concept of falsifiability of a scientific theory is discussed. First I define what is meant by falsifiability and then discuss the main criticisms of falsifiability and how the science developments react with the sharp edge of the restriction condition of what is defined as science. The last discussion is focusing on the limits that modern development in physics put on falsifiability.
In the context of the language study, falsifiability is the ability to make false, or incorrect statements about something., the linguistic root of the term is meaningful, in all contexts, it explains what could be able to determine if it could be wrong or not. And the philosophical meaning of the term uses the exact meaning of the word. But before we go looking for a precise definition of what is falsifiability, we discuss the situation before Karl Popper’s proposition about falsifiability as a criterion of science.
The verification as a criterion of science was dominated over a long period. According to the Philosophical Encyclopedia definition, it is a principle holding that a statement is meaningful only if it is either empirically verifiable or else tautological (i.e., such that its truth arises entirely from the meanings of its terms). Thus, the principle discards as meaningless the metaphysical statements of traditional philosophy as well as other kinds of statements—such as ethical, aesthetic, or religious principles—asserted as true but neither tautological nor known from experience. Such statements may have meaning in the sense of being able to influence feelings, beliefs, or conduct but not in the sense of being true or false and hence of imparting knowledge. According to the principle, then, a non-tautological statement has meaning only if some set of observable conditions is relevant to determining its truth or falsity; so stated, it reflects the view that the meaning of a statement is the set of conditions under which it would be true. 
Falsifiability in the philosophy of science is a standard of evaluation of scientific theories, according to which a theory belongs to science or not. This criterion is that the theory is scientific only if there is a possibility in principle to prove that it is false. Karl Popper proposes this criterion as a solution to the demarcation problem which is the problem of specifying what is science from pseudoscience. Karl Popper describes demarcation to be the key to most of the fundamental problems in the philosophy of science” . He also defines falsifiability criterion in the following manner, statements or systems of statements to be ranked as scientific, must be capable of conflicting with possible, or conceivable observations” . Popper’s motivation to propose this criterion was based on his criticism of confirmation and his opinion that a scientific theory cannot be confirmed because there still observations that are inconsistent with the experimental prediction of the theory. However, Popper’s idea was not about the number of experimental observations that could verify the theory, it is about that the theory needs to have an observation that can prove it’s inconsistently with empirical facts.
Popper argues that verification and confirmation played no role in formulating a satisfactory criterion of demarcation. Instead, Popper proposes that scientific theories are characterized by being bold in two related ways. First, scientific theories regularly disagree with accepted views of the world based on common sense or previous theoretical commitments. To an uneducated observer, for example, it may seem obvious that Earth is stationary, while the sun moves rapidly around it. However, Copernicus posited that Earth revolved around the sun. Similarly, it does not seem as though a tree and a human share a common ancestor, but this is what Darwin’s theory of evolution by natural selection claims. As Popper notes, however, this sort of boldness is not unique to scientific theories, since most mythological and metaphysical theories also make bold, counterintuitive claims about the nature of reality. For example, the accounts of world creation provided by various religions would count as bold in this sense, but this does not mean that they thereby count as scientific theories.
Regarding the discussions of limits of falsifiability, Let discuss how modern developments in physics which lead to the paradigm of science. We will discuss several factors when taken into account weaken the principle of falsifiability and put certain limits upon its general validity. The first concern is that we can not from the logical perspective conclude from a mismatch between theory and experiment that the theory is necessarily false. The error may be due to any number of other causes, known or unknown. For example, the mismatch may be due to experimental error as in the Faster than light neutrino anomaly , mistakes in calculating the predictions from the hypothesis, or auxiliary assumptions that have been made as in the irregularities in the orbit of Uranus because the existence of Neptune was not taken into account. In addition, experimental facts themselves are theory-laden. So, it cannot test a theory against experimental facts, independent of a theory. These assumptions and conditions of testing a theory can be so numerous that falsifying a theory, in a strictly logical sense, is often practically impossible.
The second concern with falsifiability is that, if it is strictly applied, it excludes from science certain hypotheses that are valuable to investigate, such as the hypothesis of proton decay in SU(5) symmetry theories. Although it can experimentally confirm the hypothesis of proton decay, it is not falsifiable because, no matter how long experiments fail to observe proton decay , there will always remain the possibility that it still could decay, and it is only possible to falsify specific bounds on its half-life (some estimates this half-life with a value bigger than universe age). Even though the hypothesis of proton decay is not falsifiable, it is valuable to investigate since an observation of proton decay would falsify the Standard Model of modern physics which is the best-known physics at this stage. Thus, it is not good scientific practice to make a policy of uniformly dismissing any claim as an unscientific claim simply because it is not, taken alone, a falsifiable hypothesis.
The last limit that modern physics put on falsifiability is that it excludes older theories that are, strictly speaking, false but still useful within limited domains where they remain valid approximations. Newton’s theory of gravity, for example, is strictly speaking falsely because it predicts motions that are not precisely correct as they neglect relativistic effects. Nonetheless, Newton’s theory is still considered scientific because its predictions are within the bounds of experimental error in most practical circumstances. So, even if a theory is, strictly speaking, false, that does not imply that it is unscientific or no longer approximately valid. Other examples of this problem are all the physics laws that in principle have their limitations and most of them are not valid in all contexts. Even the standard model of modern physics predicts that neutrino is a massless particle, but the experimental observation verifies that it has a mass. This does not mean that it is wrong in all context as its all other predictions are experimentally confirmed as true. So a general theory that includes the standard model is required, and it is what the scientific community is trying to find. They ignore the criterion of falsifiability not because they abounded it but because it is not effective enough to deal with the modern development and current situation of physics.
 Britannica, T. E. (2016, April 26). Verifiability principle. Retrieved April 19, 2018, from https://www.britannica.com/topic/verifiability-principle
 Popper, Karl, 1962. Conjectures and refutations. The growth of scientific knowledge, New York: Basic Books, page 42.
 Popper, Karl, 1962. Conjectures and refutations. The growth of scientific knowledge, New York: Basic Books, page 39.
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