Descartes; In a Nutshell
Firstly, I’m going to say that what Descartes wrote in “Meditations of Philosophy”, the documents from which the famous quote is extracted, does not govern his beliefs. The statements provided in these documents are resources regarding solipsism and scepticism, but he does not believe in solipsism, instead he merely believes that it’s a possibility considering that external truths can not be proven to the extent that they are infallible (for example; my senses are always playing up on me, how do I know that my senses are manipulating and I’m simply misinterpreting them?)
The conclusion which Descartes brought in his writings was very conclusive, and it basically rationalised both realism and extremist philosophies such as solipsism by integrating the two. Essentially, what Descartes was trying to say is that; even if people do not exist, or if the external world is the legitimate reality, it does not matter. It does not matter because we can still observe the external world, even if it isn’t real, and we can still obtain knowledge which is compatible with pieces of knowledge.
In a sense, the resolution which Descartes founded is much like semantics: It doesn’t particularly matter if a word may not mean what I believe it to be, so long as I can identify with it and use it as though it is a legitimate, fully functional word. Descartes, in some respects, refuted solipsism and radical sceptical beliefs with these meditations. As well as that, he helped carve the future for science and modernist philosophy in western culture, and that’s why a lot of people hold such realist beliefs. Whether or not this reality is “real”, or if we cannot absolutely prove the truth of things, it is still aside from the fact that we can still perceive something and, from that “something”, gather truths which don’t conflict with other truths and consider them as knowledge.
Reality is only real inasmuch as our definition of “reality”; generally people’s definition of reality is true existence, or true life – Descartes would say that reality is no more than what we can perceive and evaluate.