blind and powerful instinct of nature, they always suppose the very images presented to the senses to be the external objects, and never entertain any suspicion that the one are nothing but representatives of the other. But this universal and primary opinion of all men is soon destroyed by the slightest philosophy, which teaches us that nothing can ever be present to the mind but an image or perception. So far, then, we are necessitated by reasoning to contradict the primary instincts of nature, and to embrace a new system with regard to the evidence of our senses. But here philosophy finds herself extremely embarrassed, when she would obviate the cavils and objections of the sceptics. She can no longer plead the infallible and irresistible instinct of nature, for that led us to quite a different system, which is acknowledged fallible, and even erroneous, and to justify this pretended philosophical system by a chain of clear and convincing argument, or even any appearance of argument, exceeds the power of all human capacity. Do you follow the instinct and propensities of nature in assenting to the veracity of the senses? But these lead you to believe that the very perception or sensible image is the external object--(Idealism.) Do you disclaim this principle in order to embrace a more rational opinion, that the perceptions are only representations of something external? You here depart from your natural propensities, and more obvious sentiments; and yet are not able to satisfy your reason, which can never find any convincing argument from experience to prove that the perceptions are connected with external objects--(Scepticism.)"