In essence, we receive what we expect to receive from our senses. In addition to this, physical faults can affect how or what we interpret through our sensory organs: myopias, deafness, even just wearing gloves – all these restrict our senses and can lead us to come to conclusions based on what we think we know.
This can lead to problems when we encounter a problem that does not make sense if we rely on our sight or hearing alone. A classic example of this would be optical illusions such as ‘The Elephant with Five Legs’ or ‘The Impossible Triangle’ – they create situations that we know in our heads are impossible but our eyes are telling us must be true because we can see it.
In this situation, using rationalism instead of empiricism would lead us to a more sensible conclusion because we would use what we already know. However, rationalism assumes that what we already know is true.
Descartes questioned what could be known by doubting every idea before he could verify it. In the end, the only thing he could conclude as being solid fact was that he doubted in the first place which led him to the idea of “I think, therefore I am.” Except there was a problem was this theory – by claiming to think before concluding that he did actually exist, Descartes presumed that a piece of information was true before verifying that it was, simply by saying ‘I think’.
This concept of self is something that is very hard to prove – we cannot demonstrate it empirically, much as we cannot demonstrate that our mind holds thoughts or that our hearts supposedly hold emotion. These are instances that would be deemed false by the more scientific empiricism, as they do not adhere to the strict rule of ‘We must see it to believe it’, but true by the more logical reasoning of rationalism, because we already know that we have these things and they must come from somewhere.
In essence, Descartes tried to get to the issue of ‘self’ rationally without falling back on the scientific theory that it must be physically evident to be true.
However, the main question is when does the data we are provided with rationally become information we can be sure of? Is true knowledge raw data, concluded information or a combination of the two? In some circumstances, using the Coherency Theory of Truth can establish whether a new piece of information is trustworthy: if the new information fits with previously established truths then it must be true.
Nonetheless, this still leaves us with the issue of how we can determine information as truth – if our senses can be deceived and logic based on inaccurate information then it could be argued that neither are more effective ways of establishing knowledge. Perhaps, it is more a case of understanding when to use which method – rationalism when our senses are compromised and empiricism when we cannot be certain in what we already know.
