|1738 edition of the Treatise|
This problem leads Hume to consider the representational position that there are two objects — first, the perceptions (ideas) to which we have direct access through the senses; and second, the independent objects which give rise to the ideas but are not directly perceived. Being an empiricist, Hume argues that we cannot have knowledge of the causal relationship between the independent objects and our perception of them unless we have a direct sense experience of this relationship. But we can’t perceive or sense objects which by definition we can’t perceive.
In Part 4 of Book 1 of the Treatise, Hume reveals his skeptical positions. Here’s a passage from Section II, Part 4, “Of Scepticism With Regard to the Senses,” in which he professes skepticism regarding our ability to perceive the causal relationship between our ideas and the objects in external world:
I begun this subject with premising, that we ought to have an implicit faith in our senses, and that this wou'd be the conclusion, I shou'd draw from the whole of my reasoning. But to be ingenuous, I feel myself at present of a quite contrary sentiment, and am more inclin'd to repose no faith at all in my senses, or rather imagination, than to place in it such an implicit confidence. I cannot conceive how such trivial qualities of the fancy, conducted by such false sup|positions, can ever lead to any solid and rational system… What then can we look for from this confusion of groundless and extraordinary opinions but error and falshood? And how can we justify to ourselves any belief we repose in them?In the next passage he includes the operations of reason in his gloomy skeptical outlook:
THIS sceptical doubt, both with respect to reason and the senses, is a malady, which can never be radically cur'd, but must return upon us every moment, however we may chase it away, and sometimes may seem entirely free from it. 'Tis impossible upon any system to defend either our understanding or senses; and we but expose them farther when we endeavour to justify them in that manner. As the sceptical doubt arises naturally from a profound and intense reflection on those subjects, it always encreases, the farther we carry our reflections, whether in opposition or conformity to it.The question in my mind is did Hume realize where he was going when he began working on the Treatise? Or did his skepticism develop during the course of writing the Treatise?