To have any prospect of succeeding in the study of ethics then we will have to look to authors that are read and discussed. David Hume’s works are widely discussed and read and admired, so by looking at what he did say we can learn a great deal about our modern ethic. His main move in the Treatise was to assert that the faculty of moral discernment was sentimental in nature, not rational.
Take any action allow’d to be vicious: Wilful murder, for instance. Examine it in all lights, and see if you can find that matter of fact, or real existence, which you call vice. In which-ever way you take it, you find only certain passions, motives, volitions and thoughts. There is no other matter of fact in the case. The vice entirely escapes you, as long as you consider the object. You never can find it, till you turn your reflection into your own breast, and find a sentiment of disapprobation, which arises in you, towards this action. Here is a matter of fact; but ’tis the object of feeling, not of reason. It lies in yourself, not in the object. So that when you pronounce any action or character to be vicious, you mean nothing, but that from the constitution of your nature you have a feeling or sentiment of blame from the contemplation of it.
— David Hume, A Treatise of Human Nature, 3.1.1 Moral Distinctions Not Deriv’d from Reason
The next question is, Of what nature are these impressions, and after what manner do they operate upon us? Here we cannot remain long in suspense, but must pronounce the impression arising from virtue, to be agreeable, and that proceding from vice to be uneasy. Every moments experience must convince us of this. There is no spectacle so fair and beautiful as a noble and generous action; nor any which gives us more abhorrence than one that is cruel and treacherous. No enjoyment equals the satisfaction we receive from the company of those we love and esteem; as the greatest of all punishments is to be oblig’d to pass our lives with those we hate or contemn. A very play or romance may afford us instances of this pleasure, which virtue conveys to us; and pain, which arises from vice.
— David Hume, A Treatise of Human Nature, 3.1.2 Moral Distinctions Deriv’d from a Moral Sense
This makes no sense, and Austen shows why this is drivel, and takes us back to Butler’s insight that motives need to be analysed. This is not to say that ethics is in any way an exclusively rational process, and Austen was at least as satirical of cold-hearted, selfish prudence. Ethics requires the balanced operation of head and heart, founded if anything in the reality that nobody wants to suffer and that our own propensities to make other people suffer will ultimately lead to our own suffering.
The following thought experiment may help to see why sentiment alone can’t be trusted as the final arbiter in ethical matters. Imagine that a nuclear missile command centre is being inspected in the middle of an exercise, and the inspecting officer trips up, falling onto the launch mechanism, which for the sake of this improbable scenario is armed, so the missiles get launched with terrible consequences. Was this a mass murder or a horrible accident? On the face of it, it looks like an accident, but suppose the investigators uncover some evidence that the officer who fell on the launch mechanism had fantasised about staging such an accident—now it looks quite different. These are two cases where the appearance are clear cut but it would be easily possible to construct delicate scenarios where it is not clear at all and one would be forced (as happens in many criminal trials) to painstakingly analyse and weigh up the evidence. Such an exercise will be aiming to reconstruct the motive. Only in trivial cases can ethics be safely determined by sentiment.
Such a thought experiment isn’t enough though. The predisposed mind easily dismisses this kind of example as an exercise in sophistry—saying, for example, that the point that Hume was making was that we may have to work a bit to lay out the facts, but once that is done, it is the feeling of repugnance at the heinous crime that drives us to demand justice; in the end, sentiment is the driver.
For this reason we need real ethical philosophers to drive home the folly of this kind of thinking, for centuries of it have given us a taste for the irrationally sentimental. Practical philosophy calls for a practical context where the philosophy student can ‘have a go’ and see how they get on, in ‘practical’ situations and a novel provides the perfect vehicle for these purposes, drawing the reader into the world created by the author, placing them in the hot-seat and testing their judgement. This judgment then gets played out in the critical literature as each critic makes the case for their own ethics, their own reading of the novel.
No novelist has succeeded in engaging her critics and readers in this way as much as Jane Austen. She has certainly helped shape my own ethics and behaviour, and there is plenty of evidence that she has an equal ability to passionately and thoughtfully engage a popular and an academic audience (and the academics have proven to be no less passionate than the popular audience and the popular audience no less thoughtful, whether in approving or disapproving of her art).
And Austen shared Butler’s classical ideas of ethics. It would be easy enough to pile up the quotations illustrating that ethical matters hung on a minute scrutiny of motivations in Austen’s novels. Here we see Edmund at the opening of the second volume of Mansfield Park, fessing up to Sir Thomas his part in the theatricals, realizing that however easy it was to justify his part—that the outer circumstances called for his participation once it was clear that the play was going ahead and that his participation would avoid enlarging the party. But he knew by this stage that his motivation was contaminated by a desire to vicariously make love to Mary under the guise of acting, and a jealousy at the prospect of anyone else doing so in his place.
Edmund’s first object the next morning was to see his father alone, and give him a fair statement of the whole acting scheme, defending his own share in it as far only as he could then, in a soberer moment, feel his motives to deserve, and acknowledging, with perfect ingenuousness, that his concession had been attended with such partial good as to make his judgment in it very doubtful. He was anxious, while vindicating himself, to say nothing unkind of the others […].
Mansfield Park (20.1)
This however is still at the level of theorizing—saying rather than showing—but Austen’s art was more subtle this, and more practical, providing for the reader that is so inclined an ethical assault course to engage the sentiments and challenge the judgement of the reader.