Ideas of Werner Heisenberg, by Theme

[German, 1901 - 1976, The great physicist, joint developer of quantum mechanics in 1926.]

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6. Mathematics / C. Sources of Mathematics / 4. Mathematical Empiricism / b. Indispensability of mathematics
If it can't be expressed mathematically, it can't occur in nature?
     Full Idea: The solution was to turn around the question How can one in the known mathematical scheme express a given experimental situation? and ask Is it true that only such situations can arise in nature as can be expressed in the mathematical formalism?
     From: Werner Heisenberg (Physics and Philosophy [1958], 02)
     A reaction: This has the authority of the great Heisenberg, and is the ultimate expression of 'mathematical physics', beyond anything Galileo or Newton ever conceived. I suppose Pythagoras would have thought that Heisenberg was obviously right.
7. Existence / D. Theories of Reality / 1. Realism
Quantum theory shows that exact science does not need dogmatic realism
     Full Idea: It is only through quantum theory that we have learned that exact science is possible without the basis of dogmatic realism.
     From: Werner Heisenberg (Physics and Philosophy [1958], 05)
7. Existence / D. Theories of Reality / 3. Anti-realism
Quantum theory does not introduce minds into atomic events
     Full Idea: Certainly quantum theory does not contain genuine subjective features, it does not introduce the mind of the physicist as a part of the atomic event.
     From: Werner Heisenberg (Physics and Philosophy [1958], 03)
     A reaction: This should be digested by anyone who wants to erect some dodgy anti-realist, idealist, subjective metaphysics on the basis of the Copenhagen interpretation of quantum mechanics.
8. Modes of Existence / C. Powers and Dispositions / 2. Powers as Basic
A 'probability wave' is a quantitative version of Aristotle's potential, a mid-way type of reality
     Full Idea: The 1924 idea of the 'probability wave' meant a tendency for something. It was a quantitative version of the old concept of 'potentia' in Aristotelian philosophy ...a strange kind of physical reality just in the middle between possibility and reality.
     From: Werner Heisenberg (Physics and Philosophy [1958], 02)
     A reaction: [compressed] As far as I can see, he is talking about a disposition or power, which is exactly between a mere theoretical possibility and an actuality. See the Mumford/Lill Anjum proposal for a third modal value, between possible and necessary.
9. Objects / B. Unity of Objects / 2. Substance / a. Substance
We can retain the idea of 'substance', as indestructible mass or energy
     Full Idea: One could consider mass and energy as two different forms of the same 'substance' and thereby keep the idea of substance as indestructible.
     From: Werner Heisenberg (Physics and Philosophy [1958], 07)
9. Objects / C. Structure of Objects / 2. Hylomorphism / b. Form as principle
Basic particles have a mathematical form, which is more important than their substance
     Full Idea: The smallest parts of matter are not the fundamental Beings, as in the philosophy of Democritus, but are mathematical forms. Here it is quite evident that the form is more important than the substance of which it is the form.
     From: Werner Heisenberg (Physics and Philosophy [1958], 04)
     A reaction: Heisenberg is quite consciously endorsing hylomorphism here, with a Pythagorean twist to it.
14. Science / D. Explanation / 2. Types of Explanation / e. Lawlike explanations
We give a mathematical account of a system of natural connections in order to clarify them
     Full Idea: When we represent a group of connections by a closed and coherent set of concepts, axioms, definitions and laws which in turn is represented by a mathematical scheme we have isolated and idealised them with the purpose of clarification.
     From: Werner Heisenberg (Physics and Philosophy [1958], 06)
     A reaction: Attacks on the regularity theory of laws, and the notion that explanation is by laws, tend to downplay this point - that obtaining clarity and precision is a sort of explanation, even if it fails to go deeper.
14. Science / D. Explanation / 2. Types of Explanation / j. Explanations by reduction
You can only explain the qualities of large objects using entities which lack those qualities
     Full Idea: It is impossible to explain the manifest qualities of ordinary middle-sized objects except by tracing these back to the behaviour of entities which themselves no longer possess these qualities.
     From: Werner Heisenberg (Ancient Thought in Modern Physics [1937], p.119), quoted by William Lycan - Consciousness 8.10
     A reaction: Compare the similar wonderful remark by Lucretius (Idea 5713). If we accept this as a general principle for all of nature (including us) - and I do - then it is silly to complain that consciousness isn't found in basic physics.
26. Natural Theory / D. Laws of Nature / 2. Types of Laws
Seven theories in science: mechanics, heat, electricity, quantum, particles, relativity, life
     Full Idea: Science has seven closed systems of concepts and axioms: Newtonian mechanics; the theory of heat; electricity and magnetism; quantum theory; the theory of elementary particles; general relativity; and the theory of organic life.
     From: report of Werner Heisenberg (Physics and Philosophy [1958], 06) by PG - Db (ideas)
     A reaction: [my summary of pp.86-88 and 92] It is interesting to have spelled out that there are number of 'closed' theories, which are only loosely connected to one another. New discoveries launch whole new theories, instead of being subsumed.
27. Natural Reality / A. Classical Physics / 2. Thermodynamics / a. Energy
Energy is an unchanging substance, having many forms, and causing all change
     Full Idea: Energy is a substance, since its total amount does not change. ...Energy can be changed into motion, into heat, into light and into tension. Energy may be called the fundamental cause for all change in the world.
     From: Werner Heisenberg (Physics and Philosophy [1958], 04)
     A reaction: Grandiose stuff. I remain unconvinced that Heisenberg (clever fellow, I'm told) has any idea of what he is talking about.
Energy is that which moves, and is the substance from which everything is made
     Full Idea: Energy is the substance from which all elementary particles, all atoms and therefore all things are made, and energy is that which moves.
     From: Werner Heisenberg (Physics and Philosophy [1958], 04)
     A reaction: I'm not sure what energy is, but I like this because it says that nature is fundamentally active. Nothing makes sense without that basic assumption (on which Leibniz continually insists).
27. Natural Reality / B. Modern Physics / 2. Electrodynamics / b. Fields
Maxwell introduced real fields, which transferred forces from point to point
     Full Idea: In the theory of fields of force one came back to the older idea, that action is transferred from one point to a neighbouring point. ...With Maxwell the fields of force seemed to have acquired the same degree of reality as the body's of Newton's theory.
     From: Werner Heisenberg (Physics and Philosophy [1958], 06)
27. Natural Reality / B. Modern Physics / 2. Electrodynamics / d. Quantum mechanics
Radiation interference needs waves, but radiation photoelectric effects needs particles
     Full Idea: How could it be that the same radiation that produces interference patterns, and therefore must consist of waves, also produces the photoelectric effect, and therefore must consist of moving particles.
     From: Werner Heisenberg (Physics and Philosophy [1958], 02)
27. Natural Reality / B. Modern Physics / 4. Standard Model / a. Concept of matter
Position is complementary to velocity or momentum, so the whole system is indeterminate
     Full Idea: The knowledge of the position of a particle is complementary to the knowledge of its velocity or momentum. If we know one with high accuracy we cannot know the other with high accuracy; still we must know both for determining the behaviour of the system.
     From: Werner Heisenberg (Physics and Philosophy [1958], 03)
     A reaction: This is the famous Uncertainty Principle, expressed in plain language by the man himself. At this point we lost our grip on the prospects of determining the behaviour of natural systems.
An atom's stability after collisions needs explaining (which Newton's mechanics can't do)
     Full Idea: The first new model of the atom could not explain the most characteristic features of the atom, its enormous stability. No planetary system following the laws of Newton's mechanics would ever go back to its original configuration after a collision.
     From: Werner Heisenberg (Physics and Philosophy [1958], 02)
It was formerly assumed that electromagnetic waves could not be a reality in themselves
     Full Idea: The idea that electromagnetic waves could be a reality in themselves, independent of any bodies, did at that time not occur to the physicists.
     From: Werner Heisenberg (Physics and Philosophy [1958], 07)
     A reaction: 'At that time' is when they thought the waves must travel through something, called the 'ether'.
27. Natural Reality / C. Space-Time / 1. Space / d. Substantival space
So-called 'empty' space is the carrier of geometry and kinematics
     Full Idea: From our modern point of view we would say that the empty space between the atoms was not nothing; it was the carrier of geometry and kinematics.
     From: Werner Heisenberg (Physics and Philosophy [1958], 04)
     A reaction: I'm not sure what the 'carrier of geometry and kinematics' means, but it is interesting that he doesn't mention 'fields' (unless they carry the kinematics?)
27. Natural Reality / C. Space-Time / 2. Time / f. Presentism
In relativity the length of the 'present moment' is relative to distance from the observer
     Full Idea: In classical theory we assume past and future are separated by an infinitely short time interval called the present moment. In relativity it is different: future and past are separated by a finite time interval dependent on the distance from the observer.
     From: Werner Heisenberg (Physics and Philosophy [1958], 07)
     A reaction: Not sure I understand this, but it is a revelation to realise that not only is time made relative to observers, but the length of the 'present moment' also becomes relative. The infinitesimal present moment has always bothered me.