On The Possibility Of Perceptual Knowledge

This paper attempts to demonstrate the possibility of perceptual knowledge,and in response to the skepticism about perceptual knowledge.Perceptual knowledge is acquired through the sensory and formed by the reasoning,it is about physical properties of external objects.Perceptual knowledge is the foundation in our knowledge about the outside world,since it is influenced by different cognitive contexts,changes in physical properties of external objects themselves,and the sensory has its fallibility,thus the perceptual knowledge has been challenged by the skepticism for a long time.Through the analysis and comparison of several theories of perceptual knowledge,this paper will sort out theoretical resources to defend the perceptual knowledge,and in response to skepticism.The main problem that the skepticism about perceptual knowledge is whether beliefs about things appear to us are in accord with beliefs about the physical world.The skepticism deems that beliefs about things appear to us can not constitute deductive reasons,or inductive reasons to defend beliefs about the physical world,thus the perceptual knowledge is impossible.So the response can be divided into two parts.One is about the content of perceptual beliefs,another is the form of reasoning about perception knowledge.On the first point,it can be roughly divided into two kinds of theories,one is doxastic theories,the other is non-doxastic theories.This paper will mainly analyze foundations theories among doxastic theories and direct realism among non-doxastic theories.According to foundations theories,beliefs about things appear to us are basic beliefs,belies about the physical world are non-basic beliefs.We use basic beliefs to justify non-basic beliefs.The problem is that it does not tell us how can beliefs about things appear to us link to the physical world.The direct realism can answer this question.According to it,the way things appear to us constitutes a reason to justify the belief about things appear to us incorrigibly,the belief about things appear to us constitutes a prima-facie reason to justify the belief about the physical world defeasibly.This paper will specify these concepts of the direct realism.On the second point,defeasible reasoning is different from deductive and inductive reasoning,and it can be used as a logic tool to defend the reasoning form of perceptual knowledge.This paper will specify its main concepts and describe its reasoning form.The direct realism and defeasible reasoning are proposed by John L.Pollock.In conclusion,the direct realism and defeasible reasoning as theoretical resources can response to the skepticism,and defend the possibility of perceptual knowledge.