John Locke, a philosopher who published a book, titled "An Essay Concerning Human Understanding" in this book Locke talks about sense knowledge. What is sensitive knowledge? Locke's definition of sensible knowledge is “Knowledge is the perception of the agreement or disagreement of two ideas” (IV, I, 2) knowledge is the agreement or disagreement of two ideas of which you are aware. The “ideas” Locke mentions in this definition are things you immediately perceived, things you immediately became aware of. For example, a person sees a chair in front of him, directly perceives the chair, and those things you perceive are your ideas (the chair). In this article I will show how Locke successfully defends himself. In this book Locke talked about knowledge, Locke underlines that there are three degrees of knowledge: intuitive, demonstrative and sensible. Intuitive knowledge was what you saw as it is, without any intervention. For example, the sun, the sun shines so brightly in front of you that you have no doubt or even doubt that it was not the sun. Demonstrative knowledge is the opposite of intuitive knowledge, demonstrative knowledge has interventions or connection of one idea with another Locke also states that demonstrative knowledge can also be called reasoning. Finally, the focus of this article is sensible knowledge which Locke defines sensible knowledge as a perception of agreement or disagreement of two ideas. The “ideas” that Locke mentions in these definitions are the object you are perceiving, the object or thing you see in front of you. Sense knowledge in Locke's definition is that external things exist because of sense ideas. Therefore, the proof that external objects exist is due to our senses (e.g. smell, taste, touch... etc.). Locke states that there is a limit to sensible knowledge, this limit is that a person can verify whether an object exists only if it is in his field of vision. Whereas sensory ideas are produced by an external object, Locke states that sensory ideas go against our will. For example, pain, if you get hit, you feel pain and you have no control or choice not to feel pain. Descartes is another philosopher like Locke, he also talked about the proof of the existence of external objects. Unlike Locke, Descartes believes that pure intellect is the best evidence, while Locke believes that sensible knowledge is the best evidence. I agree with Locke because even though Descartes opposes Locke's theory and says that Locke relies too much on the sensory idea, Descartes' theory also relies a little'