DONALD HOFFMAN: In science and in our personal life, the theories that we build to navigate the world always have assumptions. And the theories depend critically on those assumptions. If we change the assumptions, we will get a very different picture of the world.

And in the case of science, the assumptions are the place where the theory stops. Explanation stops. So if you are a physicalist, for example, you will say, please grant me, say, space-time and quantum fields. And if you grant me that, then I can explain a whole lot of things. I can try to explain chemistry, biology, and so forth.

Then we might have to go deeper. We find that, say, general relativity and quantum field theory are in conflict. And so we need a deeper theory that we might use to get both. And so many physicists are trying to find a deeper set of assumptions, not to assume space-time, but to assume something deeper and show that space-time emerges.

So it's all about knowing exactly what you're -- in fact, the assumptions are the critical part in a scientific theory and in personal theories. Knowing what your assumptions are is, in some sense, the most essential first move. We always have to critically examine our assumptions.

In the case of science, we call them assumptions but I'll call them miracles. Because from the point of view of science, the assumptions are where explanation stops. The theory has nothing deeper to say.

So why, in Einstein's theory, does space and time exist? There's no answer. It's a miracle. Grant me that miracle, then I can explain all this other beautiful stuff that Einstein explained.

We're now looking for a deeper miracle, right? Something deeper than space-time for which then space-time will not be a miracle. Space-time will emerge as an explanation. But whatever that deeper thing is will be the new miracle.

So all of our explanations in personal life and in science, always start with assumptions, but let's call them what they are. They're miracles of the theory. And so you have to choose those miracles very, very carefully. And once you've chosen them very, very carefully, the structure will follow from that. So that's why they're so important.

All the time I and my colleagues, in the work we're doing in science, I'm always going back and questioning my assumptions. And here's one reason why we should do that. If we look back at human history, we see that we are quite consistent. We get it wrong.

We assumed the earth was flat until 2,500 years ago, 2,400 years ago. Everybody thought the earth was flat. We made assumptions that were false. And they led to theories that were false.

Then we thought the earth was the center of the universe for the next 2,000 years. And we were not willing to question that assumption. It took brave people like Galileo and Copernicus to question it. Some people were burned at the stake. Galileo was imprisoned.

We don't like to question our assumptions. They are very, very dear to us. And we don't like to do it. But it's the most important thing that we could possibly do.

And I would say moving forward, that in science and spirituality, the relationship between science and spirituality, spiritual traditions have insights that have been gained over thousands of years of practice and meditation and so forth, but they have their own assumptions. And it's very important when we're dealing with the biggest questions of who are we? Why are we here? Why is there evil? What is life about? The big, big questions that the spiritual traditions examine.

It seems there, more than any where else, we need to really look at our assumptions, try to make them as precise as possible, so that we can find out precisely where we're wrong. And I would say that was the bottom line with assumptions. Question them. Make your assumptions as absolutely precise as you possibly can. And then confidently go wherever those assumptions take you and find out precisely where you're wrong. And then go back and modify your assumptions.

I always assume I'm wrong. Looking back at human history, we're consistent, as I said. There's no reason for me to believe I'm an exception. I'm almost surely wrong. But the idea is to keep questioning assumptions and then getting a deeper and deeper, and more comprehensive understanding.