Read here about the human scale, the "normal" default scale at which people are assumed to operate.


The human scale is the set of physical quantities, and quantities of information, characterizing the human body, its motor, sensory, or mental capabilities, and human social institutions. It is this scale that provides us with meaningful comparisons or "anchor points" with which we comprehend other scales.

Human scale measurements are on the order of:
  • Distance: one to two metres (human arm's reach, stride, height)
  • Attention span: seconds to hours
  • Life span: approximately seventy years
  • Mass: kilograms
  • Force: newtons
  • Pressure: one standard atmosphere
  • Temperature: around 300 Kelvin (room temperature)

Middle as a Name for the Human Scale

The human scale, from which we aggregate and disaggregate reality, forms a kind of middle to all that we perceive.

Goldilocks World

Some philosophers call the human scale a "Goldilocks World" named after the fairy tale heroine who chooses between things too large, too small, and just right. Our human scale is termed "just right." See stories.

Middle World

Richard Dawkins coined the term "Middle World" to refer to the world at the human scale.

"Science has taught us, against all intuition, that apparently solid things, like crystals and rocks, are really almost entirely composed of empty space. And the familiar illustration is the nucleus of an atom is a fly in the middle of a sports stadium and the next atom is in the next sports stadium. So it would seem the hardest, solidest, densest rock is really almost entirely empty space, broken only by tiny particles so widely spaced they shouldn't count. Why, then, do rocks look and feel solid and hard and impenetrable? As an evolutionary biologist I'd say this: our brains have evolved to help us survive within the orders of magnitude of size and speed which our bodies operate at. We never evolved to navigate in the world of atoms. If we had, our brains probably would perceive rocks as full of empty space. Rocks feel hard and impenetrable to our hands precisely because objects like rocks and hands cannot penetrate each other. It's therefore useful for our brains to construct notions like "solidity" and "impenetrability," because such notions help us to navigate our bodies through the middle-sized world in which we have to navigate. Moving to the other end of the scale, our ancestors never had to navigate through the cosmos at speeds close to the speed of light. If they had, our brains would be much better at understanding Einstein.

I want to give the name "Middle World" to the medium-scaled environment in which we've evolved the ability to take act... We are evolved denizens of Middle World, and that limits what we are capable of imagining. You find it intuitively easy to grasp ideas like, when a rabbit moves at the -- sort of medium velocity at which rabbits and other Middle World objects move, and hits another Middle World object, like a rock, it knocks itself out....

See more information, see Richard Dawkins.


Primack coined the term "Midgard" to refer to Middle World. He wrote:

Transcendence” should not be thought of as an imaginary leap to some place “outside” the universe. Transcendence is what happens many times within this universe, every few powers of ten. For example, on the atomic and subatomic scales, “human” means nothing. There is no humanness to our atoms. Whether atoms are inside us, inside a rock, or drifting through space, is all the same to them. On the atomic scale, therefore, even inside our own bodies we do not exist. “We” are something that transcends atoms. In the same way the universe as a whole transcends familiar Midgard. Amazingly, in this interpretation the difference between spiritual and physical becomes – in an approximate way – quantifiable with powers of ten. Things larger than about 10^12 cm, or smaller than about 10^-2 cm, can only be known through science and only experienced, if at all, spiritually. This includes most of the universe." [1]

For more information, see Primack.

Mathematical Scale and the Human Scale

Mathematicians and scientists use very large and small numbers to describe physical quantities, and have created even larger and smaller numbers for theoretical purposes. Many of the objects of scientific interest in the universe are much larger than human scale (stars, galaxies) or much smaller than human scale (molecules, atoms, subatomic particles). Similarly, many time periods studied in science involve time scales much greater than human timescales (geological and cosmological time scales) or much shorter than human timescales (atomic and subatomic events).

A primary application of [[|scalometer|scalometers]] is to elucidate these vast or tiny numbers and help readers assesss their likely impact on our human scale.

Human Architectural Scale

Humans interact with their environments based on their physical dimensions, capabilities and limits. The field of anthropometrics (human measurement) has unanswered questions, but it's still true that human physical characteristics are fairly predictable and objectively measurable. Buildings scaled to human physical capabilities have steps, doorways, railings, work surfaces, seating, shelves, fixtures, walking distances, and other features that fit well to the average person.

Humans also interact with their environments based on their sensory capabilities. The fields of human perception systems, like perceptual psychology and cognitive psychology, are not exact sciences, because human information processing is not a purely physical act, and because perception is affected by cultural factors, personal preferences, experiences, and expectations. So human scale in architecture can also describe buildings with sightlines, acoustic properties, task lighting, ambient lighting, and spatial grammar that fit well with human senses. However, one important caveat is that human perceptions are always going to be less predictable and less measurable than physical dimensions.

Human scale in architecture is often deliberately violated for the following reasons.
  • Monumental effect. Buildings, statues, and memorials are constructed in a scale larger than life as a social/cultural signal wherein the subject matter is also larger than life. An example is the Rodina (Motherland) statue in Volgograd (Stalingrad).
  • Aesthetic effect. Many architects, particularly in the Modernist movement, design buildings that prioritize structural purity and clarity of form over concessions to human scale. This became the dominant American architectural style for decades. One example is Henry Cobb's John Hancock Tower in Boston.
  • Automobile access. Commercial buildings that are designed to be legible from roadways assume a radically different shape from buildings designed tobe legible for a walking human on a sidewalk. The human eye can distinguish about 3 objects or features per second. A pedestrian steadily walking along a 100-foot (30-meter) length of department store can perceive about 68 features; a driver passing the same frontage at 30 mph (13 m/s or 44 ft/s) can perceive about six or seven features. Auto-scale buildings tend to be smooth and shallow, readable at a glance, simplified, presented outward, and with signage with bigger letters and fewer words. This urban form is traceable back to the innovations of developer A. W. Ross along Wilshire Boulevard in Los Angeles in 1920.

Human Common Sense

"Common sense" ideas tend to relate to events within human experience, and thus commenurate with these scales. There is thus no commonsense intuition of, for example, interstellar distances or speeds approaching the speed of light.

Weights and measures tend to reflect human scale, and many older systems of measurement featured units based directly on the dimensions of the body. The metric system, which is based on other more reproducible physical quantities, still attempts to keep its base units within the range of human experience. Other systems, such as Planck units are useful for theoretical purposes, but are not useful for everyday purposes.

Thompson on the Human Scale

D'Arcy Thompson, On Growth and Form p.5:

"Since this book was written, some five and twenty years ago, certain great physico-mathematical concepts have greatly changed. Newtonian mechanics and Newtonian concepts of space and time are found unsuitable, even untenable or invahd, for the all but infinitely great and the all but infinitely small. The very idea of physical causation is said to be illusory, and the physics of the atom and the electron, and of the quantum theory, are to be elucidated by the laws of probability rather than by the concept of causation and its effects. But the orders of magnitude, whether of space or time, within which these new concepts become useful, or hold true, lie far away. We distinguish, and can never help distinguishing, between the things which are of our own scale and order, to which our minds are accustomed and our senses attuned, and those remote phenomena which ordinary standards fail to measure, in regions where (as Robert Louis Stevenson said) there is no habitable city for the mind of man. It is no wonder if new methods, new laws, new words, new modes of thought are needed when we make bold to contemplate a Universe within which all Newton's is but a speck. But the world of the living, wide as it may be, is bounded by a famihar horizon within which our thoughts and senses are at home, our scales of time and magnitude suffice, and the Natural Philosophy of Newton and Gahleo rests secure." [2]

Links and References

[1] Review of "The View from the Centre of the Universe by Nancy Ellen Abrams and Joel R. Primack", Popular Science website Copyright © Creativity Unleashed Limited 2005, Last update 05 June 2007. Retrieved 22 April 2012.

[2] On Growth and Form by D'Arcy Thompson. For a full text, click here:

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