However, the reliability and validity of scientific method lead to some philosophical problems, for example the Hume’s induction problem. Hume considered that the knowledge comes only from sensory experience; people cannot rely on a priori knowledge (Okasha, 2002:24). As Hume said, if the most direct source of scientific results are the induction of the experience of facts, then the correctness of any scientific conclusions are unreliable. Because scientists cannot guarantee the conclusions from limited experience is truth. As Popper said that if a judgment is scientific, then this judgment must be falsifiable, because any empirical verification of the facts is not enough to confirm the correctness of the judgment (Spiegel, 1998:74). Therefore, for a scientific conclusion only has two states, has been falsified or has not been falsified. If it has not been falsified, then the conclusion is not confirmed at this time, hence it is unreliable. If it has been falsified, then the conclusion is wrong, its reliability does also not exist.
However, the objectivity of scientific method is not always exists in scientific community, it can be affected by some factors. For instance, funding is widespread influence on objectivity of science. Sometimes if scientists pay too much attention on the investment may affect their objective judgment,