While some of my co-bloggers and illustrious guests have been confronting the very difficult issue of science and morality, I’ve been drifting elsewhere. Now that my new book A Tear at the Edge of Creation has been out for about a month, some readers have begun writing to me with their ideas and opinions. I’ve been also giving talks at various places and have gotten feedback that way as well.
From this collage of views, I’d like today to address in more detail an issue that lies at the very foundation of what science is about, an issue that makes for heated discussion: What do we (physicists and scientists in general) mean by “laws of nature?" The issue is more complicated than it seems and it will take much more than the lines below to disentangle it. But we have to start somewhere.
Authorities both in science and in philosophy have very conflicting views on the nature of the laws of Nature. Before I launch into my own views on the issue, let me quote a few key ideas.
First, from Max Planck, who introduced the notion of the quantum in 1900:
There is a real world, independent of our senses; the laws of Nature were not invented by man, but forced upon him by the natural world. They are the expression of a rational world order.
Clearly, Planck believed that we don’t invent such laws, but merely discover them. This would mean, for example, that intelligent aliens would stumble onto the same set of laws. They may represent them differently, but their essence would be identical. This position assumes a universality of knowledge: There is a unique body of information out there and, given time, intelligent beings will get more and more of the same thing. Of course, aliens may get the same set of laws that we do even if they are not universal, but that would involve contingency. Planck’s position would resonate with believers: If God created the universe and its laws then, of course, these are universal. By discovering these laws were are, as has often been stated, “unveiling the mind of God.” In fact, it was in this God-given framework that the notion of “laws of Nature” first appeared, as part of Descartes’s work.
Another group that would commit to Planck’s view are the believers in a hidden code of Nature, a set of fundamental laws and principles that describe the essence of physical reality. This code has many names. Familiar ones are “Final Theory” or “Theory of Everything.” The finality here implies two things that I find surprising: first, that there is an end to the search; second, that we humans can get there. I strongly disagree with both.
It’s in fact easier to find opinions that diverge from Planck’s. Einstein himself knew that our theories are fictions, in the sense that two or more explanations can do the job of describing phenomena equally well:
The fictitious character of the principles are made quite obvious by the fact that it is possible to exhibit two essentially different bases [e.g. Schrödinger’s and Heisenberg’s quantum mechanics] each of which in its consequences leads to a large measure of agreement with experience.
Feynman would say that “Every scientific law, every scientific principle, every statement of the results of an observation is some kind of summary which leaves out details, because nothing can be stated precisely.”
The philosophers Karl Popper and Thomas Kuhn would go further (perhaps Kuhn a bit too far). Popper wrote that scientific theories are not “the digest of observations but inventions — conjectures boldly put forward for trial, to be eliminated if they clashed with observations.”
So, there you have it, a very brief sampling of what goes on.
Jumping into the debate, what can be said about the laws of Nature? (I will have to address what are the laws some other time...) No question that we observe regular patterns in Nature, from the very small to the very large. Some of these patterns relate to symmetries, which can be expressed mathematically.
However, when a physicist says “energy is conserved” (to use the same example as my last posting, but in a different context) we only “know” this to be a fact within the accuracy of our measurements. And even though, as our measuring tools advance, our measurements improve in time, they are always limited to a certain precision. As a consequence, we cannot turn the statement “energy is conserved” into an absolute statement.
From this pragmatic perspective, there are no absolute statements at all, even in the context of the physical sciences. We construct models to describe, as best as we can, the reality we are able to measure. We can’t even say that this measured reality is the “ultimate” reality, even if you believe such a thing exists. As humans, we are bound to see the world forever out of focus. The glasses we invent may sharpen the image somewhat, but we will always be missing details here and there.
This means that we cannot take the “human” out of the picture completely. Even as we strive to make science as objective as possible, we are the sole players here, both pitchers and batters.
If there are such things as intelligent aliens (and we don’t really know either way), and if they have an interest in describing Nature quantitatively, they certainly would arrive at something that we recognize as science.
But it will be their “fiction,” based on their cognitive abilities and windows into reality. They have their glasses and we have ours. Even if their image may be sharper than ours, it will never be perfect. Every potential mind out there in the cosmos is bound to its own perspective of things.