This is a historical post.
In my last post I argued that, contrary to popular belief, science is not actually about observation.
Here I wish to taken an aside and discuss two of the main competing schools of epistemology (i.e. the theory of how we gain knowledge). The traditional view of science was founded by Francis Bacon. This school of thought is (as Popper describes it anyhow) is as follows:
According to Bacon, the nature or essence of the method of the new science of nature, the method which distinguishes and demarcates it from the old theology and from metaphysical philosophy, can be explained as follows:
Man is impatient. He likes quick results. So he jumps to conclusions.
This is the old, the vicious, the speculative method. Bacon called it ‘the method of anticipations of the mind’. It is a false method, for it leads to prejudices. (The term ‘prejudice’ was coined by Bacon.)
Bacon’s new method, which he recommends as the true way to knowledge, and also as the way to power, is this. We must purge our minds of all prejudices, of all preconceived ideas, of all theories – of all those superstitions, or ‘idols’, which religion, philosophy, education, or tradition may have imparted to us. When we have thus purged our minds of prejudices and impurities, we may approach nature. And nature will not mislead us. For it is not nature that misleads us but only our own prejudices, the impurities of our own minds. If our minds are pure, we shall be able to read the Book of Nature without distorting it: we have only to open our eyes, to observe things patiently, and to write down our observations carefully, without misrepresenting or distorting them, and the nature or essence of the thing observed will be revealed to us.
This is Bacon’s method of observation and induction. To put it in a nutshell: pure untainted observation is good, and pure observation cannot err; speculation and theories are bad, and they are the source of all error. (Myth of the Framework, p. 84)
Popper labels the Baconian view of science “Observationalism.” Popper goes on to say that the Baconian view of science (which is still held widely today even by many scientists) is actually a religious dogma.
Bacon, I suggest, was not a scientist but a prophet. … He had the vision of a new age, of an industrial age which would also be an age of science and of technology. …Thus the new religion of science held a new promise of heaven on earth – of a better world which with the help of new knowledge, men would create for themselves. Knowledge is power, Bacon said, and this idea, this dangerous idea, of man’s master over nature – of men like gods – has been one of the most influential of the ideas through which the religion of science has transformed our world. (Myth of the Framework, p. 85-86)
Bacon was thus a founder of a short of anti-Church – one that proved useful, but not necessarily scientific in nature.
However, as an epistemology, Baconian Observationalism, and its foundation of induction, is disproven.
As Popper points out:
Bacon, the philosopher of science, was, quite consistently, an enemy of the Copernican hypothesis. Don’t theorize, he said, but open your eyes and observe without prejudice, and you cannot doubt that the Sun moves and the Earth is at rest. (Myth of the Framework, p. 84-85)
Why Is Observationalism Wrong?
Popper criticizes the Baconian view on several grounds. First of all, it’s impossible to purge our minds of prejudice. Only after we have made a scientific advance can we then, retroactively, tell that we held onto a prejudice (such as the Earth not moving) that was hindering our progress. “For there is no criterion by which we could recognize prejudices in anticipation of this advance.” Therefore, “The rule ‘Purge yourself of prejudice!’ can therefore have only the dangerous result that, after having made an attempt or two, you may think that you have succeeded.”
Worse yet, if you actually did purge your mind of all theories, your mind wouldn’t be pure, it would be empty. (Myth of the Framework, p. 86)
This explains why I have traditionally come down so hard against people saying things such as:
“The world is split into two kinds of people, the curious and fundamentalists.”
“I’m not like those crazy <fill in the blank group> because I follow the evidence.”
Views like this truly are often dangerous because they miss the point that everyone at every given moment believes they are the curious non-“fundamentalists” that is following the evidence. Usually statements like the above are defensive in nature. A way of avoiding the truth about oneself. In fact, Popper goes one further:
There is no such thing as ‘pure’ observation, that is to say, an observation without a theoretical component. All observation – and especially all experimental observation — is an interpretation of facts in the light of some theory or other. (Myth of the Framework, p. 86)
In other words, all observation are, as Popper puts it, “theory-impregnated.” “There is no pure, disinterested, theory-free observation,” he adds. (Myth of the Framework, p. 8) 
Worse yet, Bacon claimed that science was based on induction. To this day, it is still common to hear scientists claim that science is justified based on inductive reasoning. Science finds something to be true – say gravity causes masses to attract – and tests it over and over. After many thousands of observations we eventually can inductively assume that the theory of gravity is basically true and start to rely on it.
Popper points out the fallacy of this thinking:
…no amount of observation of white swans establishes that all swans are white (or that the probability of finding a non-white swan is small.) …Thus repetitive induction is out: it cannot establish anything. (Myth of the Framework, p. 104-15) 
It is within this framework that Popper’s actual views on Falsification must be understood. He apparently is not suggesting that science must be refutable, but rather that until a theory holds the quality of refutability, observations neither hurt not help the theory. That is to say, “observation should count for nothing unless the theory is testable.” (Myth of the Framework, p. 89)
This far more conservative view of refutability – as it relates only to observation – makes much better sense of Popper’s epistemology. This should replace the popular (and false) view that scholarship and science are ‘testable’ and other things are not.
But if Observationalism and Inductivism are out, what is science? And how can faith in it be justified?
 As Popper puts it:
…Bacon was the prophet of the secularized religion of science. He replaced the name ‘God’ by the name ‘Nature’, but he left almost everything else unchanged. Theology, the science of God, was replaced by the science of Nature. The laws of God were replaced by the laws of Nature, God’s power ws replaced by the forces of Nature. And at a later date, God’s design and God’s judgment were replaced by natural selection. … In short, God’s omnipotence and omniscience were replaced by the omnipotence of nature and by the virtual omniscience of natural science. … Bacon was the prophet, the great inspirer of the new religion of science, but he was not a scientist. (Myth of the Framework, p. 82-83)
…Bacon is the spiritual father of modern science. Not because of his philosophy of science and his theory of induction, but because he became the founder and prophet of a rationalist church – a kind of anti-church. (Myth of the Framework, p. 195)
 Popper also puts it this way: “Indeed, there is no such thing as an uninterpreted observation, an observation which is not theory-impregnated.” (Myth of the Framework, p. 58)
 This quote is probably the source of Nassim Nicholas Taleb’s title for his excellent book: The Black Swan: The Impact of the Highly Improbable. This is an excellent book worth a read. Taleb does an excellent job pointing out that even a scientifically based Inductivism – namely statistical analysis – is often fatally flawed because it is used on phenomena that it should never have been applied to.