In Book One of David Hume's Treatise on Human Nature he makes some assertions about the nature of the self and how we can come to have knowledge of the self. Later, in the Appendix to the Treatise, he contrasts self and substance and admits that two principles that seem necessary to his discussion of self are contradictory.
For Hume, the burning question is "From what impression do we derive the idea of self?" He makes the assertion that, though other philosophers feel that the concept of self is simple, obvious, and constantly present, the question of originating impression goes unanswered. In Section VI, he writes:
For from what impression could this idea be derived? This question it is impossible to answer without a manifest contradiction and absurdity; and yet it is a question, which must necessarily be answered, if we would have the idea of self pass for clear and intelligible, It must be some one impression, that gives rise to every real idea. But self or person is not any one impression, but that to which our several impressions and ideas are supposed to have a reference.
He then continues, stating that whatever impression it was upon which the self is based must necessarily be constant throughout one's entire life. There is no such constant impression (according to Hume), rather, life is a constant succession of different and varying impressions, none ever-present.
Hume's next target is how, or indeed if, these individual impressions are connected. He searches in vain for a connection and, declaring each impression distinct, finds none.
His next, long, section is devoted to the relationships between self,
substance, soul, and identity. He addresses both identity (lack of variation over time) and succession of objects in time, and claims that they are often "confounded with each other." Asserting that this is a mistake, he warns the reader not to confuse them, as doing so would trivialize the matter of the nature of self. He sums it up as follows:
Thus the controversy concerning identity is not merely a dispute of words. For when we attribute identity, in an improper sense, to variable or interrupted objects, our mistake is not confined to the expression, but is commonly attended with a fiction, either of something invariable and uninterrupted, or of something mysterious and inexplicable, or at least with a propensity to such fictions. What will suffice to prove this hypothesis to the satisfaction of every fair enquirer, is to shew from daily experience and observation, that the objects, which are variable or interrupted, and yet are supposed to continue the same, are such only as consist of a succession of parts, connected together by resemblance, contiguity, or causation.
Finishing up this section, Hume expands his notion of identity. Considering chunks of material, he demonstrates that though some material may be removed from or added to the whole, the mass' identity remains constant. He extends this idea to embrace living things, saying that their identity remains constant over time "though there be not one particle of matter, or figure of its parts the same."
Clarification or Further Confusion?
In the Appendix, Hume clarifies his thoughts on the self.
Unfortunately this clarification of principles conflicts with his
earlier section on the self. He realizes this and is at a loss to
make them consistent. He begins his lament thusly:
When I turn my reflection on myself, I never can perceive this self without some one or more perceptions; nor can I ever perceive any thing but the perceptions. It is the composition of these, therefore, which forms the self.
We can conceive a thinking being to have either many or few perceptions. Suppose the mind to be reduced even below the life of an oyster. Suppose it to have only one perception, as of thirst or hunger. Consider it in that situation. Do you conceive any thing but merely that perception? Have you any notion of self or substance? If not, the addition of other perceptions can never give you that notion.
He is reiterating that composition of perceptions does not magically
produce the concept of self or identity. Indeed, in conclusion to the
previously discussed Section VI, he admits:
The whole of this doctrine leads us to a conclusion, which is of great importance in the present affair, viz., that all the nice and subtle questions concerning personal identity can never possibly be decided, and are to be regarded rather as grammatical than as philosophical difficulties.
Making distinct the concepts of self and substance, Hume cites his previous assertion that under a change of substance (in living things), the concept of self remains constant. He does not defend it, however, saying that he cannot say how they are distinct from one another. The plot thickens:
So far I seem to be attended with sufficient evidence. But having thus loosened all our particular perceptions, when I proceed to explain the principle of connexion, which binds them together, and makes us attribute to them a real simplicity and identity; I am sensible, that my account is very defective, and that nothing but the seeming evidence of the precedent reasonings could have induced me to receive it. If perceptions are distinct existences, they form a whole only by being connected together. But no connexions among distinct existences are ever discoverable by human understanding.
He then comes to the meat of the section, presenting conflicting summaries of his previously stated principles:
In short there are two principles, which I cannot render consistent; nor is it in my power to renounce either of them, viz., that all our distinct perceptions are distinct existences, and that the mind never perceives any real connexion among distinct existences. Did our perceptions either inhere in something simple and individual, or did the mind perceive some real connexion among them, there would be no difficulty in the case.
Admitting that he is at a loss to explain this discrepancy, Hume
leaves the matter open for resolution by others or himself, perhaps
after more "mature reflection."
Bravery Despite Contradiction
Knowing that the Appendix of the Treatise was written after the body we can surmise that Hume wrote it after reflecting upon what he had written earlier. Despite that, it is not a correction of his earlier thoughts; rather, it is a distillation to the essence of his philosophy. Unfortunately for him, at the core of his work lies a contradiction that, in his own words, he is unable to make consistent or renounce.
Hume believes in both of his principles even though they contradict
each other. He deems it more valuable to propose a theory that is not completely internally consistent but which explains many observations than not to espouse his philosophy at all. It is fortunate for his readers that he chose to highlight the contradiction; lesser writers might have hoped that nobody would notice it.
Great Thinkers: Hume
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