Sean Carroll

That is to say, they don't have perfectly precise, well-defined energies. That's part of the fun of quantum mechanics. in exactly the same way that an electron itself, which if we imagine that it is exactly in a perfectly definite state of energy, it will then not be in a perfectly definite state of position. We think of the electron as being in a superposition of many different positions.

these photons are typically going to be in superpositions of many different energies. So the energy has to be pretty close to the right answer to poke the electron around in the right way. But there's probably some uncertainty around that exact right answer. And as long as the electron's energy is within that uncertainty band, you have a probability of making this happen.

these photons are typically going to be in superpositions of many different energies. So the energy has to be pretty close to the right answer to poke the electron around in the right way. But there's probably some uncertainty around that exact right answer. And as long as the electron's energy is within that uncertainty band, you have a probability of making this happen.

Remember, all of quantum mechanics is about probabilities for these things happening. And likewise, yes, the electrons are going to be moving back and forth. They're going to have Doppler effects in the photons that they emit and absorb. But that's sort of helping them, right?

Remember, all of quantum mechanics is about probabilities for these things happening. And likewise, yes, the electrons are going to be moving back and forth. They're going to have Doppler effects in the photons that they emit and absorb. But that's sort of helping them, right?

In the sense that if you have many different molecules and they, you know, molecular energy levels are generally tightly compressed. There's a lot of them. So it's not just like the one or two that you see in the cartoon of the hydrogen atom and so forth, right?

In the sense that if you have many different molecules and they, you know, molecular energy levels are generally tightly compressed. There's a lot of them. So it's not just like the one or two that you see in the cartoon of the hydrogen atom and so forth, right?

So if you have the molecules moving or the photons moving, so there's not only some uncertainty in energy but some shift in energy because of the Doppler effect, it is more likely that some of the photons are going to be in the right band to do the action.

So if you have the molecules moving or the photons moving, so there's not only some uncertainty in energy but some shift in energy because of the Doppler effect, it is more likely that some of the photons are going to be in the right band to do the action.

I suspect that—and I don't know this for sure, so you should talk to a real biologist—but I suspect that in the eye, when there is an electrochemical receptor that fires, the probability of that happening per photon, I suspect, is pretty small. I don't know that, but we have a lot of photons in the world. I think that there is some controversy.

I suspect that—and I don't know this for sure, so you should talk to a real biologist—but I suspect that in the eye, when there is an electrochemical receptor that fires, the probability of that happening per photon, I suspect, is pretty small. I don't know that, but we have a lot of photons in the world. I think that there is some controversy.

Now that I'm thinking about it, there's some uncertainty about, you know, is the eye sensitive enough to detect a single photon? And maybe the answer is sometimes it is, sometimes it isn't, depending on what's going on. But anyway, I think the basic lesson here is there's a lot of uncertainty in quantum mechanics, and this is an example where that actually helps us out.

Now that I'm thinking about it, there's some uncertainty about, you know, is the eye sensitive enough to detect a single photon? And maybe the answer is sometimes it is, sometimes it isn't, depending on what's going on. But anyway, I think the basic lesson here is there's a lot of uncertainty in quantum mechanics, and this is an example where that actually helps us out.

Cole Giusto says, in the big picture, you emphasize that emergent phenomena are still real even if they're not fundamental. How do you differentiate important ontological disagreements from semantics? In what way do you think real has a definite meaning that is worth arguing for? You know, whether it's worth arguing for or not, I think that's a bit of a judgment call, right? And very often...

Cole Giusto says, in the big picture, you emphasize that emergent phenomena are still real even if they're not fundamental. How do you differentiate important ontological disagreements from semantics? In what way do you think real has a definite meaning that is worth arguing for? You know, whether it's worth arguing for or not, I think that's a bit of a judgment call, right? And very often...

arguments about whether or not something is real aren't worth arguing for. I don't want to argue about it, honestly. I just want to be clear about what I mean. So if someone wants to say the tables and chairs are not real, I'm not going to expend my precious time here on this earth convincing them that they're wrong.

arguments about whether or not something is real aren't worth arguing for. I don't want to argue about it, honestly. I just want to be clear about what I mean. So if someone wants to say the tables and chairs are not real, I'm not going to expend my precious time here on this earth convincing them that they're wrong.

I'm just going to say, look, what I mean by real is it plays some causal role in the universe. It helps me understand what will happen. As I've given the example many times before, if someone says there is a table in the room over here and there are chairs around that table, then instantly certain things appear in my mind like, oh, so we could go sit at the chairs around the table.

I'm just going to say, look, what I mean by real is it plays some causal role in the universe. It helps me understand what will happen. As I've given the example many times before, if someone says there is a table in the room over here and there are chairs around that table, then instantly certain things appear in my mind like, oh, so we could go sit at the chairs around the table.

We could put our beverages onto the table and it would hold them up. right? So that information that is useful about dealing with the world, predicting what will happen, anticipating what comes next, strategizing between different alternative things, actions we could take and things like that, that's what I mean by real, right?