Scientific knowledge is generated through empirical verification, and from a logical positivist perspective, the distinction between science and non-science depends on verifiability. A regression study of salmon can be used to illustrate this process.
How is scientific knowledge generated? There are different explanations for this, depending on the philosophical perspective of science. One of them is the logical positivist view, where the meaning of a scientific statement is determined by its empirical verifiability. This view emphasizes that scientific knowledge is accumulated solely on the basis of empirical evidence. Logical positivists consider scientific statements to be meaningful only if they can be empirically verified, otherwise they are considered unscientific or meaningless. Let’s look at the process of generating scientific knowledge from a logical positivist perspective through the study of salmon migration.
Scientists wanted to know how salmon return to the place where they were born, and Indians believed that supernatural forces caused them to return. However, the scientists believed that this explanation had no scientific significance because it could not be empirically verified. This is consistent with the logical positivist critique that supernatural explanations cannot be objectively verified through empirical testing. Thus, scientists began to reject supernatural explanations and focus on verifiable hypotheses. They came up with explanations such as the visual hypothesis, the earth’s magnetic field hypothesis, and the olfactory hypothesis.
To test the visual hypothesis, scientists caught and marked salmon arriving at two rivers in the northwestern United States, the Issaquah and the Forks. They then divided the salmon into two groups. One group was blindfolded. The other group was unblindfolded, and both groups were released into fresh water further downstream from the confluence of the two rivers. The experiment showed that the number of salmon returning to the capture site was not significantly different between the two groups.
This result showed that the visual hypothesis was not supported, and the scientists were able to draw an important conclusion from the experiment: salmon homing does not rely solely on visual information. However, the rejection of one hypothesis does not mean the end of the research. Scientific inquiry advances by finding alternative hypotheses and repeating experiments. Scientists realized that pigeons use the earth’s magnetic field to find their way home, so they hypothesized that salmon also use the earth’s magnetic field. However, the results of the experiments did not support the geomagnetic field hypothesis.
After the failure of this hypothesis, scientists began to explore other possibilities. This led to the hypothesis that the salmon’s sense of smell could play an important role. To test the olfactory hypothesis, which was inspired by the eel study, scientists conducted the same experiment where they tested the visual hypothesis. They caught salmon from two rivers, one group of which was nasally plugged and the other unplugged. After releasing the salmon, they recaptured them at the same place where they were first captured as they returned to freshwater to spawn. They categorized the recaptured salmon according to whether they were snorkeled or not and where they were first captured. After comparing them to the deduced results, the scientists found that their hypothesis was statistically supported.
Many scientists use a process like this to generate new knowledge. They first encounter a puzzling phenomenon that cannot be explained by current knowledge. They create a tentative explanation based on prior knowledge that is similar to the current situation. It’s important to note that a scientific hypothesis is not just a guess, but must be presented in a verifiable form. Otherwise, the hypothesis cannot be the subject of scientific inquiry. Then, come up with a way to test the tentative explanation. We then collect data and compare it to the results deduced from the tentative explanation. If the hypothesis is not supported, the process is repeated in a circular fashion, and new scientific knowledge is generated as a result of this cyclical process. Hypotheses are very important because they are verified by experiments and observations. This is why logical positivists set verifiability as an important criterion for distinguishing science from non-science.
After all, scientific knowledge develops gradually through a constant process of verification and disproof. Validated hypotheses are accepted temporarily, but can always be revised by new evidence. This process shows that science is a self-correcting discipline that is constantly in the pursuit of truth.
