Science is an organized process that builds and develops knowledge in the form of predictions and testable scientific models of the universe. It is the field concerned with the measurement and study of physical laws and their variations, and the application of those laws to living organisms. It involves the application of math and other scientific methods in order to obtain knowledge about nature and how it works. The goal of science is to discover the truth by making direct observations and measurements of nature in its working and then applying that knowledge to further understand and improve our understanding of that subject.
One of the most fundamental facts about science is that it is empirical, or based on observation. The scientific method is not based on any sort of prior or independent truth. There is no theory in science that could be “proved” or “established” before there has been any independent scientific investigation of it. Rather, all theories are based on observation and the ability to measure and record certain characteristics of nature. As Albert Einstein pointed out in his Relativity (1918), “If the theories of celestial mechanics are to be accepted at all, they must be accepted as given.”
Science is not static but progressive. Just as each day brings new discoveries and understanding of the natural world, theories within science also change and evolve over time. For example, over the last century or so, a number of theories in physics and chemistry have been proposed and become generally accepted. However, the big question is, how do we know which theories are the true and which ones are simply a product of human interpretation and modeling? How do we determine if a model is meaningful and can provide us with an accurate description of the natural world and how it works?
Two broad methods are used in science to examine a hypothesis: deductive reasoning and induction. Deductive reasoning is used when an investigator collects data from nature and applies general laws to it to search for a specific result. inductive reasoning is used when an investigator collects data that is relevant to their hypothesis and applies the laws of deductive reasoning to those data to search for a specific result. Although both types of reasoning can be used together, deductive reasoning is considered the more common form. When combining the two methods, however, it is often more efficient and lends itself better to falsification (testing the null hypothesis).
How do scientists use a scientific method to test a hypothesis? First, they must determine whether the hypothesis is reasonable and well-supported by the available evidence. Based on this information, a hypothesis can be tested using observational methods (the results of which can be statistically related to the hypothesis) or by experimental methods (which include performing the experiment and analyzing its results). Once a reasonable hypothesis has been determined, a scientist can test it using either deductive or inductive reasoning. Here are some examples:
If observations show that a tree grows in a certain way, and the hypothesis states that this must be the way the natural world works, then scientists can test this using deductive reasoning. If they observe that this is the only kind of tree that grows in this environment, then it can be tested using induction. For instance, if they find that a particular kind of tree only grows in certain environments, then it can be proved that it does indeed exist by the principles of induction. In order to obtain further support for their hypothesis, scientists use more advanced techniques like molecular biology, fossil evidence, and genetics to test the validity of their findings.