NATURE|Vol 436|7 July 2005 ESSAY

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The mental UniverseThe only reality is mind and observations, but observations are not of things. To see the Universe as itreally is, we must abandon our tendency to conceptualize observations as things.

Richard Conn Henry

Historically, we have looked to our reli-gious leaders to understand the meaningof our lives; the nature of our world. WithGalileo Galilei, this changed. In establish-ing that the Earth goes around the Sun,Galileo not only succeeded in believingthe unbelievable himself, but also con-vinced almost everyone else to do thesame. This was a stunning accomplish-ment in ‘physics outreach’ and, with thesubsequent work of Isaac Newton, physicsjoined religion in seeking to explain ourplace in the Universe.

The more recent physics revolution ofthe past 80 years has yet to transform general public understandingin a similar way. And yet a correct understanding ofphysics was accessible even to Pythagoras. According toPythagoras, “number is allthings”, and numbers are men-tal, not mechanical. Likewise,Newton called light “particles”,knowing the concept to be an‘effective theory’ — useful, nottrue. As noted by Newton’sbiographer Richard Westfall:“The ultimate cause of atheism,Newton asserted, is ‘this notionof bodies having, as it were, acomplete, absolute and independent real-ity in themselves.’” Newton knew of New-ton’s rings and was untroubled by what isshallowly called ‘wave/particle duality’.

The 1925 discovery of quantummechanics solved the problem of the Uni-verse’s nature. Bright physicists were againled to believe the unbelievable — this time,that the Universe is mental. According toSir James Jeans: “the stream of knowledgeis heading towards a non-mechanical real-ity; the Universe begins to look more like agreat thought than like a great machine.Mind no longer appears to be an acciden-tal intruder into the realm of matter... weought rather hail it as the creator and gov-ernor of the realm of matter.” But physi-cists have not yet followed Galileo’sexample, and convinced everyone of thewonders of quantum mechanics. As SirArthur Eddington explained: “It is diffi-cult for the matter-of-fact physicist toaccept the view that the substratum ofeverything is of mental character.”

In his play Copenhagen, which bringsquantum mechanics to a wider audience,

Michael Frayn gives these word to NielsBohr: “we discover that... the Universeexists... only through the understandinglodged inside the human head.” Bohr’swife replies, “this man you’ve put at thecentre of the Universe — is it you, or is itHeisenberg?” This is what sticks in the craw of Eddington’s “matter-of-fact”physicists.

Discussing the play, John H. MarburgerIII, President George W. Bush’s scienceadviser, observes that “in the Copenhageninterpretation of microscopic nature, thereare neither waves nor particles”, but thenframes his remarks in terms of a non-exis-tent “underlying stuff ”. He points out thatit is not true that matter “sometimes

behaves like a wave and sometimes like aparticle... The wave is not in the underly-ing stuff; it is in the spatial pattern of detec-tor clicks... We cannot help but think of theclicks as caused by little localized pieces ofstuff that we might as well call particles.This is where the particle language comesfrom. It does not come from the underly-ing stuff, but from our psychological predisposition to associate localized phe-nomena with particles.”

In place of “underlying stuff ” there havebeen serious attempts to preserve a mater-ial world — but they produce no newphysics, and serve only to preserve an illu-sion. Scientists have sadly left it to non-physicist Frayn to note the Emperor’s lackof clothes: “it seems to me that the viewwhich [Murray] Gell-Mann favours, andwhich involves what he calls alternative‘histories’ or ‘narratives’, is precisely asanthropocentric as Bohr’s, since historiesand narratives are not freestanding ele-ments of the Universe, but human con-structs, as subjective and as restricted intheir viewpoint as the act of observation.”

Physicists shy from the truth becausethe truth is so alien to everyday physics. Acommon way to evade the mental Uni-verse is to invoke ‘decoherence’ — thenotion that ‘the physical environment’ issufficient to create reality, independent ofthe human mind. Yet the idea that anyirreversible act of amplification is neces-sary to collapse the wave function isknown to be wrong: in ‘Renninger-type’experiments, the wave function is col-lapsed simply by your human mind seeingnothing. The Universe is entirely mental.

In the tenth century, Ibn al-Haytham ini-tiated the view that light proceeds from asource, enters the eye, and is perceived. Thispicture is incorrect but is still what most

people think occurs, including,unless pressed, most physicists.To come to terms with the Universe, we must abandonsuch views. The world is quan-tum mechanical: we must learnto perceive it as such.

One benefit of switchinghumanity to a correct percep-tion of the world is the resultingjoy of discovering the mentalnature of the Universe. We haveno idea what this mental natureimplies, but — the great thing is— it is true. Beyond the acquisi-tion of this perception, physics

can no longer help. You may descend intosolipsism, expand to deism, or somethingelse if you can justify it — just don’t askphysics for help.

There is another benefit of seeing theworld as quantum mechanical: someonewho has learned to accept that nothingexists but observations is far ahead ofpeers who stumble through physics hop-ing to find out ‘what things are’. If we can‘pull a Galileo,’ and get people believing thetruth, they will find physics a breeze.

The Universe is immaterial — mentaland spiritual. Live, and enjoy. ■

Richard Conn Henry is a Professor in theHenry A. Rowland Department of Physicsand Astronomy, The Johns HopkinsUniversity, Baltimore, Maryland 21218, USA.

FURTHER READINGMarburger, J. On the Copenhagen Interpretation ofQuantum Mechanicswww.ostp.gov/html/Copenhagentalk.pdf (2002).Henry, R. C. Am. J. Phys. 58, 1087–1100 (1990).Steiner, M. The Applicability of Mathematics as aPhilosophical Problem (Harvard Univ. Press, Cambridge,MA, 1998).

Proof without words: Pythagoras explained things using numbers.

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