字幕列表 影片播放 列印英文字幕 So we've just seen that according to the 2nd Noble Truth, the source of Dukkha, the source of suffering and unsatisfactoriness is our craving, our attempt to hang on to things that don't last including pleasure and I used powdered sugar donuts as my own personal example of that. The Buddha, as we saw, said that our failure to kind of grasp this dynamic, was just another example of our failing to see the world clearly. Now in this segment of lecture one, we're going to drill down a little into the biological mechanics of craving, And of the evaporation of p, of pleasure. And we're going to ask why it is that if the Buddha was right, why it is that we do fail to get the picture about pleasure and how fleeting it is. [SOUND] Now in Buddhist writing when, when the Buddha. Talks about our failure to see things clearly. He often uses a word that is typically translated as, delusion. But I want to emphasize that sometimes that word is a little bit of an overstatement. So, for example, when I'm gazing at powdered sugar doughnuts, you know, There's no point where I'm you know, thinking that there are foreign agents conspiring to assassinate me or anything. There' not even a point where I actually think the pleasure's going to last forever. In fact, If you said, well do you think it's going to last for 10 minutes, I'd probably say no. But at the same time, as I look forward to eating those donuts, I'm thinking a lot more about the pleasure then about the evaporation of the pleasure and I'm certainly not thinking about you know, well maybe the sugar rush will subside and then [UNKNOWN] I'm just focused on that moment of pleasure. Now in other cases something more like delusion may actually happen. You know, with infatuation. If you've ever had a serious crush on someone, you, you may recall that you know, you had a pretty distorted view of things. You, you had a lot of trouble seeing any blemishes or deficiencies in the person. It was all good, right? And there was this idea that wow, should you ever be so lucky as to find yourself in a relationship with that person, everything would be better probably eternally. And you know, relationships needless to say are in fact you know, more complicated than that. And so, too, with a, with say, a job you really want. You're, you know, if you really want that thing, you're looking forward to it, thinking about all the great things it's going to bring. You're not thinking about the hassles that all jobs bring. And there may be a sense that, if you could just get this job, then you could relax. Then you will have, arrived. But of course, you haven't really arrived, you know, the gratification is not going to last forever, it never lasts forever. Now if you want to look at parts of the brain that are relevant to the failure of gratification to last forever, one obvious candidate would be the neurotransmitter dopamine. If you read much in the popular science press, you've probably read about dopamine as the pleasure chemical, the reward chemical. The true story is actually a lot more complicated than that. The effects dopamine has depend on the part of the brain you're in, which neurons are involved, which receptors are involved. And so on. There's also the question of does dopamine actually cause pleasure, or is it just correlated with pleasure. The for our purposes the, the mere correlation is pretty much enough, the fact that dopamine seems to be correlated with pleasure. so, we're going to look at a little data from a study in which they monitored very precisely the neurons in monkeys that are involved with the release of dopamine and are in a part of the brain where dopamine seems to be correlated with pleasure and reward. So what they did, they gave a little fruit juice To a monkey and here's what happened. So that is a dopemamine spike. If you want to ask, how long does that last? How, how long are we talking about along that horizontal axis? Well, that's about a third of a second of dopemine spike. So, assuming that in this monkey dopamine is correlated with pleasure. You know that's, that's pretty brief pleasure. You know if monkeys could talk he might have said this particular monkey might have said wow that was impermanent. You know? Maybe the monkey condition is very much like the human condition and pleasure just tends to evaporate pretty rapidly. And if that is the case then that's all the more reason to look at natural selection as a possible explanation for why pleasure does evaporate. You know, if, if monkeys and humans are exhibiting some of the same dynamics. [SOUND] so the question is, why does natural selection build brains like this, where pleasure is so fleeting? Why not just leave that dopamine spigot on? You could, you know, you could keep dishing out dopamine for 10 seconds, 20 seconds, in principle. But that doesn't happen. Why is that? And, and, and why do we seem, you know, not to really get the picture in our everyday lives about how rapidly the pleasure is going to dissipate. Why did natural selection design our brains like this? Now, as I've said before, whenever I say something is designed by natural selection, designed should be in quotes. Natural selection is not a conscious designer, still it does create animals that look as if they were designed by a pretty smart designer with one thing in mind, to get them to get their genes into the next generation. So it is a fair thing to do, as a kind of thought experiment, to put ourselves in the shoes of natural selection and ask If we were designing organisms, how would we design their brains? You know, if we wanted them to get their genes to their next generation. Now, granted that eating helps them do that by keeping them alive. Sex obviously helps them do that. And even with humans and non-human primates, things like elevating their social status helps them do that because it seems to be the case that in primates and some some other parts of the animal kingdom, social status is correlated with getting genes into the next generation. So it is a fair question. How would you design these brains if you were natural selection? I would submit that there are 3 principles of design, that would make sense if you want animals to reach these goals. Okay, first of all, when animals do reach the goals, they have food, they have sex they should get some pleasure. Pleasure is what reinforces behavior, makes animals more likely to do whatever led them to the goal in the first place. Principle number two, the pleasure should not last forever. Obviously if you ate one meal, and just blissed out, you know. And, and, and never felt the, the unpleasant sensation of hunger again, you would never eat again. You would die. Okay? And if you had sex and then just kind of basked in the after glow for a really long time, thinking about how wonderful it'd been, you know, and meanwhile, in your species some other animal had sex, said that was great, but you know I'm starting to feel restless, I think I'll go get some food, or do something to elevate my social status, or maybe go find some more sex. Well, that animal's going to get more genes in the next generation than you will. So these genes for restlessness and for you know, not being satisfied for very long, that that animals has are going to do better than your genes. The third principle of design. I would submit, is that animals should focus more on the pleasure that reaching goals will bring than on the subsequent evaporation of the pleasure, okay? You know obviously if you're focused on that pleasure. If you're focused on, on how good it's going to feel to reach the goal, you'll reach the goal. Whereas if you're sitting there thinking you know, the pleasure's going to be over in a nanosecond, why work so hard? Well you know, you're going to probably wind up, you know, sitting in your room alone full of ennui. Reading existential philosophy or something, you know, and that's definitely no way to get your genes into the next generation. So, I would say that these, these three principles of design they make sense in terms of natural selection and they, they help make sense of Buddhist teaching, right? The Buddha said that pleasure tends to evaporate and it leaves us unsatisfied and it seems to be the case that pleasure is designed to evaporate so that it will leave us unsatisfied and we will be motivated to go out and do more work and, and, and check off more bullet points on natural selection's agenda. The Buddha said, we seem not to get the picture about pleasure. We focus on the pleasure and not the fleetingness of the pleasure. And that to makes sense in terms of natural selection. Focusing on the pleasure is a good motivator. Okay, let's back to that monkey. Now. In the data we saw about that monkey's brain, we didn't see anything about anticipating pleasure. And that's because in that case, the monkey couldn't anticipate the pleasure, because the fruit juice came out of the blue. The monkey was not expecting it. They just dropped it on the monkey's tongue.