In the Meditations, Descartes aims to provide a solid basis for science and to justify rationalism by proving that the true source of scientific knowledge lies in the mind and not in the sense. In order to prove that the mind must be the true source of such knowledge, Descartes subjects all knowledge derived from the senses to doubt. He claims that as a child he accepted a large number of lies and then built "an entire edifice" of a "highly dubious nature" on them. He argues that these childhood prejudices arise naturally from immersion in the senses. He uses the example of optical illusions such as a stick in water appearing bent to show the unreliable nature of information gathered through the senses, and argues that we should therefore reject such information. Here, Descartes leaves it to the individual alone to evaluate the reliability of knowledge. It could be argued that the reliability of sensory data could actually be improved by corroboration with others, and that it should not simply be dismissed. Say no to plagiarism. Get a tailor-made essay on “Why Violent Video Games Should Not Be Banned”?Get an original essayIn order to provide a truly solid foundation for knowledge, Descartes feels the need to subject all knowledge to doubt and uses two thought experiments to do this. . He says we cannot doubt things we see up close and in good light, equating such doubt with madness and rejecting the possibility that he is mad. In order to cast doubt on even these perceptions, Descartes uses the dream argument, claiming that in dreams we seem to see things up close and in a good light when in reality this is not the case. However, the dream argument has been criticized on the grounds that it is an asymmetrical argument: just because we are not sure whether we are asleep when we dream, it does not necessarily follow that we do not know that we are awake when we are awake. Descartes does not stop at a posteriori knowledge: he also feels the need to question the validity of mathematics and a priori knowledge. To do this, he proposes the idea of ​​an all-powerful being capable of deceiving us even about this knowledge. Descartes rejects the idea of ​​a deceptive God, because God is by definition "good" and would not deceive us, and instead proposes an all-powerful evil demon. However, the whole idea of ​​“deception” relies on the idea that we are not deceived all the time. Accordingly, it seems that the all-powerful demon could not in fact deceive us about all a priori knowledge, because if that were the case, "deception" would not exist. In this way, Descartes seems to fail in his doubting of all a priori knowledge. By using these skeptical arguments, Descartes claims to have demolished all existing opinions and allowed himself to start from scratch and find a solid basis for knowledge. However, through this very statement, Descartes reveals that he did not doubt everything, because he continues to assume the truth of foundationalism and believes that it is possible to find a basis for knowledge, when in reality this may not be the case. Furthermore, he fails to doubt logic, memory, and language – all tools used by Descartes throughout the Meditations, indicating that his doubt is in fact not “universal”. Alternatively, one might suggest that Descartes' method of doubt is in fact too extreme. By wanting all knowledge to have mathematical certainty and discarding all sensory data, one could say that Descartes is simply setting the bar too high inmatter of knowledge. After the First Meditation, Descartes' greatest challenge seems to be defeating his evil demon. It is by contesting his own existence with the hypothesis of the evil demon that Descartes claims to find an element of certain knowledge, which will constitute the foundation of all other knowledge. He argues that the evil demon cannot deceive anything into believing that it exists when it does not, and therefore when it conceives that it is something, it cannot be anything. Descartes argues that the Cogito is indubitable, because if it is deceived by an evil demon, it must exist. If true, the Cogito is of central importance to Descartes' entire strategy: it provides an ideal starting point from which he can construct other truths. It provides some knowledge not only of our ideas, but also of a substantial existential truth, born not from experience or observation, but from thought alone. However, the Cogito has been criticized for its apparent use of a suppressed premise – namely, "all thinking things exist". '. This premise is highly questionable, because it is not clear that the existence of thoughts necessarily implies a thinker. Hume argued that we have no right to assume this, and Buddhist teaching holds that the so-called "self" is ephemeral. Alternatively, Descartes perhaps should have said "there is thought, therefore there are thoughts", rather than making an inference between thought and the existence of a thinker. Furthermore, Descartes moves away from rationalism here, since “thinking that things exist” seems to be an a posteriori observation. In this way, it is unlikely that the Cogito actually proves the existence of a self. In response to this, it has been argued that the Cogito does not use a suppressed premise and is in fact an analytical truth, with the concept of my present. existence contained in that of my thought, just as the concept of “female fox” is contained in that of “vixen”. However, if the cogito were truly analytical, nothing substantial about the world could arise from it and it could not constitute the basis of knowledge since analytical statements tell us about concepts rather than reality. Furthermore, as Kant and Russell argue, existence does not seem to be one property among other properties that can be attributed to things, but rather the condition of the possibility of having properties. This can be seen through the example of fictional characters - we can talk about characters having thoughts, and thus we can talk about non-existent thinkers while it is not possible to talk about male vixens. This suggests that there is no conceptual implication between existence and thought. Russell also argued that the Cogito is a circular argument because it assumes what it seeks to prove, using the word 'I' in an argument that seeks to prove the existence of said 'I'. Lichtenberg argued that this "I" is just a linguistic convenience, similar to the "it" in "it's raining", and that it doesn't actually refer to anything. In his failure to analyze these fundamental concepts, Descartes' project might be considered not radical enough, with empiricists arguing that he is subject to rationalist biases in viewing these concepts as innate rather than derived from experience. demon with the Cogito is also very questionable. There seems to be no reason why an all-powerful being capable of fooling Descartes about the logic of mathematics could not fool him about the logic and reasoning he used in the Cogito. Indeed, by failing to employ truly universal doubt in the first meditation and to doubt his own logic and reasoning, Descartes seems.