Empiricism is the theory of knowledge that claims that most or all our knowledge is obtained through sensory experience, rather than through rational deduction or innateness. Empiricists such as John Locke and David Hume emphasize the role of evidence and experience as the main way of justifying our knowledge claims. Therefore knowledge gained a priori is considered by empiricists to be inferior to knowledge gained a posteriori. John Locke, along with many other empiricists, postulated the idea of Tabula Rasa, or the argument that we are a blank slate at birth and all the ideas and concepts that we have, build up as we experience more and more things.
The main strength of using empiricism as a way of finding truth is that rationalism doesn’t necessarily account for the way that the world really works, whereas empiricism does. Empiricism is widely used in science as a method of proving and disproving theories. This is backed up by Galileo who stated that beliefs must be tested empirically in order to check that they work within the laws of physics. An example of this is Aristotle’s theory of motion in which he used rational thought to explain the motion of objects. He argued that each of the four terrestrial (or worldly) elements move toward their natural place and that heavier things fell faster than lighter things. Galileo disputed this, arguing that it was air resistance that was responsible for how fast things fell. This was later tested empirically on the moon when an astronaut dropped a feather and a hammer and they hit the ground at the same time. This is a strong argument for empiricism because it shows that it is much easier to see if something is true if it is tested than if reason is used alone.
However, rationalists dispute the role of empirical evidence based on its claim that we can acquire knowledge through our senses. This is because sense data is indirect and there has to be mediation between sensation and perception. There is also no way of knowing if what we are seeing is reality. Many people have experienced hallucinations or lucid dreams in their lives, in which they have been convinced of the existence of things that don’t exist. If it feels like reality while you are in the dream, how do you know what you’re experiencing now isn’t also a dream? Descartes was a rationalist and argued that there is no way of knowing if the things we are seeing and experiencing are real. If this is the case, we cannot claim to have knowledge that when we saw the hammer and the feather fall at the same speed, that this was actually the case. The only thing, according to rationalists, that we can be sure of are things that logically cannot fail to be true and only our rational minds can provide us with this information. Empiricism cannot be proved to be accurate.
David Hume argues against the claim that sense data is not accurate. A strong argument supporting Hume’s empiricism is that rationalism can only link ideas, whereas empiricism can link facts and is therefore a more useful tool in justifying knowledge claims. Under normal circumstances our senses do not lie and the more we repeat something the better idea we have of it. Rationalism is not useful in proving things to be true because it relies on logic that may or may not be true in itself and cannot account for the real world. Empiricism claims that experience can show whether a phenomenon repeats itself and therefore it abides by certain laws or it happened randomly, which is why it can be considered such a good foundation as a way of uncovering and proving facts. Rationalism, on the other hand, can only give us ideas, that may appear to be correct at first but without experimentation there is no way of telling whether the claim is correct.
Although empiricism is strong in the subject of physics, it cannot be used for complicated mathematics and algebra. Some mathematical equations are impossible to prove using the empiricist method because there is no physical way of showing the complications of the equation in an observational experiment. Rationalism solves this problem by using logic to suggest that whilst some things cannot be tested in the real world, they cannot logically fail to be true. This is true in the case of not just mathematics, but a lot of science. There are some things that at this moment in time cannot be tested scientifically, but a working hypothesis has still been created and only rationalism could have produced this. For instance, if we use the example of Galileo who disproved Aristotle’s theory of motion without having the ability of physically going to the moon and testing it himself. He did this by using noticing the logical fallacy of Aristotle’s argument and correcting it so that it was more coherent. Empiricism is only useful if it is possible for one to actually experience something and as there is much we cannot experience ourselves, rationalism is an important source for a great deal of knowledge.
Overall, it is clear that empiricism has both strengths and weaknesses. It is vital in our understanding of the world and in proving or disproving beliefs, but it cannot be used for everything, especially for answering questions based on intangible things such as the mind or theoretical mathematics. For these kinds of things rationalism would be better used and the most justified knowledge claims are those that cohere to both rational thought and empirical evidence.