Modern science came to be in the seventeenth century, where observations of nature began to be observed as facts systematically. Up until then, the authority of the Bible had been the primary factual basis for society. But it was pioneers such as Galileo who laid the foundation for modern science.
One of the first scientific discoveries was when Galileo dropped two balls of different weights from the leaning tower and proved that things fall evenly independent of their masses.
Two schools, empiricists, and positivists
John Locke, George Berkley, and David Hume were all British empiricist who argued that knowledge should be derived from ideas implanted in the mind by way of sense perception. Positivists originated from Vienna in the 1920s, and they shared the basic idea that knowledge should in some way be derived from the facts from observation but they expanded on this idea. They all believed that facts share the following three components.
- Facts are directly given to careful, unprejudiced observers via the senses.
- Facts are prior to and independent of theory.
- Facts constitute a firm and reliable foundation for scientific knowledge.
The act of seeing
It is commonly believed that the act of seeing something happen/exist provides the basis for knowledge. We assume that we know something because we trust the information of our eyes and we believe that experience is universal for everyone else who sees something happen/exist.
This belief has been disproven in several studies, which finds that people looking at the same illustration will see different things based on their current knowledge. Seeing is therefore not objective but colored by our experiences.
The recording of facts requires more than the reception of the stimuli, in the form of light rays, which impinge on the eye. It is necessary to hold the appropriate conceptual scheme and know how to apply it to what we observe. Our search for relevant facts needs to be guided by our current state of knowledge.
The fallibility of observation statements
The preceding arguments undermined the idea that scientific knowledge could be based on facts established by observations because facts are knowledge-dependent as previously argued. We cannot extract and interpret reality without a conceptual framework (experience) of what we are observing.
Our historical understanding of fire is a good example of this. Aristotle claimed that fire is among the four elements of which all objects are made. This idea remained for hundreds of years because observers thought they were observing fire directly when watching flames rise into the air and observed that fire was a part of the object. If the knowledge that provides the categories we use to describe or observations are defective, then observation statements that presuppose those categories are similarly flawed.
This is the same flaw in science that led to the belief that our planet was stationary. People believed that the world was stationary because they observed so. They did not have the conceptual knowledge to know that this was not the case. This shows that observable basis for science is not as straightforward and secure as is widely and traditionally supposed.