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What are references (preferably free and online) to the following philosophical idea (and related ideas). Note that this is my own idea, so in principle it is possible that there are no references by other authors.

Physical reality is described by its relation with measurements. But measurements can be defined only as interacting objects in physical reality. Thus the definition of physical reality and measurements are circular. Hence the physical reality cannot be exactly defined.

Related idea: As a child grows in his understanding of science, his knowledge of the laws of physics grows based on his explanation of his feelings and his explanation of his feelings is advanced by growing his knowledge of laws of physics, thus having an iterated process which may lead to understanding of physics.

See details in my blog post.

  • Nobody can say with certainty what reality is. I am leaning towards it being a simulation personally. But what we do know is that it behaves according to rules, and does so constantly. We're trapped in it, whatever it is. Science attempts to measure it and probe it so that we can eventually discover what it is. And in the meantime we gain benefits, like central heating, and keyhole surgery.
    – Richard
    May 23, 2017 at 22:33
  • Interesting about the circularity. Physical reality is what can be measured. But what does measuring measure? Physical reality. Good point. Especially because of the levels of existence. We see things at a certain scale and not at other scales. If we were a lot smaller we'd see the quarks. Whatever that means. But if as the physicists tell us it's all quarks or strings, then all this is an illusion. Our reality is merely an artifact of the resolution of our senses. This what you're thinking?
    – user4894
    May 23, 2017 at 23:39
  • Measuring is absolute, not relative. A kilometer may be useless at the scale of an ant, but it's still a kilometer. But yes, the human condition is tightly bound to our physical scale.
    – Richard
    May 23, 2017 at 23:53
  • The measurement circularity issue is well-known and has been studied by scientific structuralists, among others. "Physical reality" is a red herring here, it is about circularity in theory construction, so even empiricist anti-realists would face it. We already have a thread Measurement devices and empiricism with discussion and references.
    – Conifold
    May 24, 2017 at 3:02
  • 1
    Possible duplicate of Measurement devices and empiricism May 24, 2017 at 10:25

4 Answers 4


The more basic problem here is the mutuality of meaning and usage, as pursued by Wittgenstein. Yours is just the special case where the use is scientific.

Not only can't physical reality be defined through measurement, but basically, all definitions with enough precision are circular. There is no meaning outside of use, and there is no use without an intended meaning. We have to settle for convergence and stability maintained by some feedback mechanism for our picture of reality.

This makes an entirely 'physical' worldview difficult to identify, much less hold Is there a boundary on 'physical'?


I don't know that he makes the same arguments that you do, but George Berkeley comes to mind. He was an empiricist that rejected materialism.

In 1721, he published On Motion, which is an attack on the Newtonian ideals of absolute space, time, and as a result; motion. I think you will find this to be a good starting point for your assault on materialism.


Physical reality is described by its relation with measurements. But measurements can be defined only as interacting objects in physical reality. Thus the definition of physical reality and measurements are circular. Hence the physical reality cannot be exactly defined.

Physical reality can't be defined in terms of measurements since that would mean anything you can't measure doesn't exist, e.g. - the core of the sun and dinosaurs. You can't measure the core of the sun because no measuring instrument will survive there. You can't measure dinosaurs because they no longer exist. You could say that the examples I gave and other don't exist, but then you have to throw out all science since it all refers to unobserved and unobservable events.

A better idea about what exists was explained by David Deutsch in his book "The Fabric of Reality" chapter 4. Something exists if its existence is a consequence of our best explanations. For example, the core of the sun exists because its existence is implied by theories of stellar evolution, general relativity and other parts of physics.

In addition, explanations aren't about feelings. The core of the sun isn't a feeling I have but it is featured in explanations.

  • It seems you haven't read my article. In the sense of words I use, dinosaurs and the core of Sun can be measured.
    – porton
    Jun 30, 2017 at 14:29
  • According to your article vector fields can't be measured. Since the electromagnetic field is a vector field and all measuring instruments use such fields, this implies that absolutely nothing can be measured. This includes your eyes, your brain, and all your sense organs. so according to your theory, you're blind.
    – alanf
    Jun 30, 2017 at 15:10
  • I never said "vector fields can't be measured". I said: If there is some non-measurable vector field, this field is not a part of physical reality. I just say in my definition that non-measurable in principle things don't belong to physical reality. Please read more carefully.
    – porton
    Jun 30, 2017 at 17:39

Why is it necessary at all to define physical processes “exactly”? — They are anyway superficial interactions, are circularly defined (not to speak yet of their measurement) and may hence not have foundations in itself.

That the physical relations (or reality) in their interactions and the measurements thereof are mutually circularly defined, is not severe. The problem is rather that both the interacting physical objects and the physical measurements (which are, as you said rightly, of the same essence) are superficial relations.

This is not the case with chemical processes, which are deep acting genuine relations (which may be presented in bottles); hence physical interactions could anyway not be the foundations of physics. By the way they are anyway circular in itself (not to speak yet of measurements or feelings), as has been described in this post (the genuine relations of chemistry are explained in the link there quite below).

The mere facts of

1. the circularity of the mathematical relations (of interacting physical objects) i.e. of physical concepts itself, and

2. the circular dependence of this physical reality on the measurement of them,

are not a problem. It is the mentioned superficiality, which leads to the problem that physics may only be described by numbers or number-variables, and that we have hence no foundations in physics. It is not circularity of any kind (whether by maths itself, or in relation to measurements or feelings), which is the real problem. To draw an analogy: The problem is circularity without an Archimedian point.

— And now you may vent your anger by down voting me because you will not grasp what I say since philosophers, scientists, politicians are themselves grasped by their projections, which I have already hinted in other posts here.

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