Doubt is the only sure means of understanding truth and reality.
Questions Regarding Philosophy
On the philosophical level, Descartes adheres to a set of principles that are all consistent with his belief that doubt is the only sure way to comprehend truth and reality. These principles are outlined below. The Cartesian concept of identifying existence as such is predicated on the philosopher’s conviction that dualism is the defining element of human life, which is supported by empirical evidence. In order to demonstrate that the mind and the physical body are two distinct substances, Descartes follows the logical process of noting that the body is incapable of thinking, just as the mind is susceptible to the sensory impressions produced by the body. Simply put, the mind is a thinking thing, whereas the body is not, and as a result, the two are in some ways mutually exclusive. Descartes’ Meditations, on the other hand, represent the controversial notion that the mind can live independently of the physical body. This causes a great deal of debate; how, for example, can a mind function in any way apart from the body when the physical brain is required?

There is a metaphysical quality to the Cartesian notions, and here is where the answer rests. To be more specific, Descartes does not assert that the mind exists independently of the body; rather, he asserts that this is a possibility, given the fundamentally different natures of the two entities in question. Furthermore, this possibility is predicated on another Cartesian concept that is up for debate, namely, Descartes’s belief that his ability to doubt and reason is proof of his existence, while also perceiving the ability as confirmation of the human mind and soul as having been created by God, which is subject to debate. Being that this is the Cartesian reality, it follows that God, who is capable of anything, may allow for the existence of a human consciousness that is distinct from the body. Nonetheless, Descartes’ division of the substances is founded on rationality and science as well as his own observations. Above all else, he maintains that humans frequently and incorrectly assign mental activity to things that do not have minds, and that they also fail to recognize that the body functions in a variety of ways that are not related to conscious thought. According to the philosopher, there are undoubtedly interconnections between the mind and the body that are common, if not unavoidable, because physical behaviors reflect connections between the mind and the body. At the same time, however, Descartes maintains that it is critical to recognize that these two elements are intrinsically separate from one another, which, in turn, improves the human ability to apply doubt and reason as a means of knowing the nature of reality. Descartes’ thinking has been subjected to a great deal of criticism throughout history and continues to do so now; nonetheless, when his own reasoning processes are scrutinized, there is logic in place.

In a similar vein, John Locke depends heavily on logical progressions in order to construct a philosophical framework. A significant portion of Locke’s work is more pragmatic than that of other philosophers; he discusses concrete issues such as economics, government, and social structures, for example, in his writings. But, at the same time, his general epistemology continues to be founded on beliefs about the most fundamental truths of human life, as evidenced by his thoughts on how human ideas themselves are generated. These take on the forms of the simple and the complicated for Locke, and these conceptions are also related to his other perception, as will be demonstrated. The author begins by claiming that, logically, there may be no thoughts at all in a human being until they are provided by actual experience; the infant mind is in fact a blank slate. Sensory input, on the other hand, is the source of how rudimentary ideas are initially produced. When a youngster consumes food, he or she may come to believe that an unpleasant feeling of hunger has been gone.
When a number of simple thoughts are joined in a relational manner, complex concepts emerge; the human mind then draws conclusions by comparing and utilizing a number of different impressions to arrive at a conclusion.

If, for example, eating satisfies a child’s hunger and continues as a simple concept, this concept gets expanded when the youngster has more eating experience and realizes that certain foods have unpleasant side effects. According to Locke, this process of arriving at complex concepts by combining the simple is referred to as a mode, and there are essentially no limitations to the ways in which human minds can build upon ideas and also apply subjective reasoning in order to achieve what are thought to be true conclusions. The natures of what human beings experience and perceive are also important in this process, as indicated by Locke’s distinction between primary and secondary qualities in his book On Relationships. There is no way to develop a concept without first considering the causal impact of a quality or property, which can take one of two key forms. When it comes to the fundamental, it is that which is free of any sort of subjectivity; it exists independently of how or if it is experienced by anyone. The size and weight of a table, for example, are immutable qualities, regardless of whether or not they are recognized as such.

In contrast, when a person looks at the table and acknowledges that the wood is dark, what happens is a secondary impression, because the quality of darkness does not exist in a fixed way in the external world. Similarly, Locke asserts that color itself, while frequently regarded as a distinguishing characteristic, is inherently subject to individual interpretation. If the table is made of brown wood, the “brownness” of the wood exists only to the extent that it is seen by the person who is experiencing the table. As a result, Locke’s conception of representational realism is strengthened. Although a thing is real in the sense that it possesses certain features of a fundamental nature, human beings invariably associate concepts with it based on how they perceive various aspects of it. Fundamentally, rather than the item itself, it is the human experience of the thing that encourages beliefs about its identity. That as the human being acquires more complicated thoughts, subjectivity in assessing the realities of external objects gets more pronounced, and features that are in no way “real” take on the qualities of the real is strongly emphasized by Locke’s thinking in this regard.