"You have heard that it was said, â€˜You shall love your neighbor and hate your enemy.â€™ But I say to you, love your enemies, bless those who curse you, do good to those who hate you, and pray for those who spitefully use you and persecute you"Â Matthew 5:43-44

Boy, if there was ever a case of 'easier said than done.'

I have to actually love my enemies? Â Even if that's the weakest sense of love we can think of, it's still a big ask. Â I don't just have to forgive them for doing me wrong, I have to love them for it. Â From experience, it seems like bad feelings about people who have wronged me take a while to even soften, and there doesn't seem like much I can do to speed that process up. Â Even then, not having bad feelings about someone is still a long way from loving them.

Maybe that's just a best case scenario though.Â Jesus Christ is a moral exemplar par excellance.Â Perhaps Christianity doesn't require us to love our enemies, so much as tell us that's what we should aspire to.Â After all, the kind of hatred I feel for my worst personal or political enemies seems to be involuntary.Â If I can't help doing something, it seems a little unfair to require me to do it.

Oh, hang on; what's this a few chapters earlier?

"You have heard that it was said to the ancients, 'You shall not commit murder, and whoever commits murder shall be liable to judgment.' But I say to you that everyone who is angry with his brother shall be liable to judgment."Â Matthew 5:21-22

Well that's torn it.Â If I am angry with my brother I shall be liable to judgement, in the same way as if I was to commit murder.Â Even noting that some translations of this passage (though not the best ones) have it that I am only liable to judgement if I am angry with my brother 'without cause', that still seems like a pretty tall order.

There is an axiom in moral philosophy that 'ought' implies 'can'; if you tell me that I ought to Ï†Â you are implicitly asserting that Ï†-ing is something that is within my power to do.Â I am morally obligated to feed my cat, but I would no longer be obligated to feed my cat if she ran away.Â If I phycially (or metaphysically for that matter) can't feed my cat, then I have no obligation to do so.Â If my emotions are truly involuntary then I can't be morally obligated to attain, or refrain from attaining, any emotional states whatsoever.

Whether we can do what Jesus is asking here is going to turn on whether we think that our emotions are within our voluntary control. Â Just how realistic is it to think that we can choose whether or not to be angry with someone, or choose who we love?

The view that Jesus is indeed asking too much of us is famously shared by Freud and Kant. Â Both explicitly claimed that love 'cannot be commanded.' Â Kant reinterpreted Jesus as askingÂ onlyÂ that we have a basic respect for others as rational agents; Freud simply used the impossibly high standard of Christianity's fundamental principles as another stick to sarcastically beat religion with. Â Hume too, asserting as he did that "Reason is and ought only be the slave of the passions," would probably have chuckled smugly at the notion that our occasional bouts of anger should land us on the wrong side of Saint Peter.

The odds aren't all against the messiah on this one though.Â As with so many other important questions, we 'folk' are apparently very conflicted.Â Although we do generally consider the emotions to be beyond our immediate control, we are also apt to punish those who display emotions that are socially transgressive.Â Were you happy that someone died?Â Were you amused by a racist joke?Â Do you hate it when your friends become successful? (Morrissey, I'm looking at you...) We are apparently very happy to treat people's emotions as subject to moral assessment.

What's more, there are equally prominent thinkers who take issue with Freud's and Kant's analyses of our causal responsibility for our emotions.Â As was briefly discussed in a recent PEL episode, Sartre (and Bob Solomon, in his book The Passions, which owes a great intellectual debt to Sartre) believes that your emotions, just like the rest of your inner life, are more or less entirely under your voluntary control.Â 'Passions' for Sartre are not, as the name implies, a passive response to whatever situation you find yourselfÂ inÂ (compare passive/passions and active/actions).Â Would you rather not be the kind of person who delights in other people's failures?Â Then, according to Sartre, you can just stop being that kind of person (and, what's more, you're probably in bad faith if you don't).

If you want to claim, as Sartre and Jesus do, that we can be held accountable for our emotions, then it looks like you either have to say that (1) we are culpable for some things that are not within our immediate control or (2) our emotions are within our immediate control.Â Sartre has opted for (2).

Is this realistic though?Â Even if you can change your personality on a dime, it's another question as to whether those parts of your personality you can change in that way are the parts that dictate your emotional experience.Â Even on the strongest readings of Sartre, he's surely not going to suggest that we can change our memories.Â If a traumatic childhood experience is what makes me unreasonably angry when my neighbour covets my ox, does Sartre really think I can voluntarily remove that memory, or the effect it has on me?

For what it's worth, I don't think Sartre does think that, but this all presses the question of what exactly it would take in order for my emotions to count as being within my control.Â I'm not going to be able to give anything like a full answer to that here, because what it would take for emotions to be in my control depends to a large extent on exactly what we think emotions are.

There are currently three big players in the philosophical debate about the nature of emotion; historically there have been several more.Â Â The biggest dog in the race for most of the twentieth century, cognitivism wasÂ the view that emotions are a kind of judgement about the world.Â Fear is a judgement that an object is scary, shame the judgement that you have transgressed, and so on.Â Cogntivism is going to be very friendly to Jesus and Sartre in this argument.Â According to cognitivism, an emotion is made up of a belief, a desire and a feeling.Â Since beliefs are the kinds of things we can be blamed for having (if they are ill informed or unreasonable), it starts to look plausible that we can praise or blame people for having emotions on the basis of the appropriateness of their constituent beliefs.

The other two, recently more popular, theories about the nature of emotions are Feeling Theories and Perceptual Theories.Â As the names imply, the former says that emotions are just feelings and the latter that emotions are perceptual states, like seeing and hearing.Â On either of these theories, it's going to be a lot more difficult to praise or blame people for having particular emotions.Â Can you blame someone for feeling cold?Â Can you claim moral superiority if you have natural perfect pitch?Â If not, we've got to explain how emotions are different from other feelings or perceptions in their suitability for moral assessment.

The nature of the emotions is an incredibly fascinating subject, finely treading that treacherous tightrope between philosophy, psychology and neuroscience.Â Whether Jesus is asking too much when he tells us to love our enemies is only one question among many whose answers rely on us having a good understanding of what emotions are and what role they play in human life.

Al Baker