During the Renaissance and Enlightenment a dramatic change occurred in how humans observed and perceived the universe. The new paradigm was in large part created by Rene Descartes, who advocated a mathematical description of natural phenomena and the use of analytic thought to study nature.
The Cartesian system aspired to create a precise and complete account of natural phenomena with mathematical precision.
Descartes’ paradigm of nature was a mechanistic one — he even drew parallels between a sickly human and a poorly-manufactured clock. Cartesian reasoning works on what Hannah Arendt in The Human Condition called

the implicit assumption that the mind can only know that which it has itself produced and retains in some sense within itself.

Alfred North Whitehead called it “the outcome of common sense in retreat.”
Sir Isaac Newton synthesized the work of Copernicus, Descartes, Galileo, and Kepler to create a mathematical formula for nature — Newtonian mechanics.
Cartesian “reductionism” gave rise to the notion that physics would explain chemistry, chemistry would explain biology, and biology would explain psychology. This system worked so well over the years that by the end of the 19th century it was widely believed all natural phenomena would eventually be explained by reducing them to the sum of their particles, so to speak.
Well-oiled machinery was a fitting metaphor for the Cartesian-Newtonian paradigm, the Industrial Revolution and the cultures which grew out of it. The beauty of the mechanistic universe was in its concepts of rational order and equilibrium, and the loveliest symbol of the paradigm is always to be found in the static structure of crystals.
Reductionism and Newtonian mechanics did explain everything — until the early part of the twentieth century. The work of Maxwell, Einstein, Bohr, Heisenberg and the rest of the new physics exploded the myth of the Cartesian-Newtonian universe. There was, in the words of Paul Davis,

an explosion of ideas which shattered the cozy notions of reality that had endured for centuries. Many cherished beliefs and unquestioned assumptions were swept away. The old world view of a rational and mechanistic universe, ordered by rigid laws of cause and effect, collapsed into oblivion …

Science is dead — long live science!

Einstein said in his autobiography that the upheaval in science seemed like

the ground had been pulled out from under one; with no firm foundation to be seen anywhere, upon which one could have built.

It has been difficult for many to move from the Cartesian-Newtonian model to the Eastern-flavored world of the new science. (The furor over Fritjof Capra’s The Tao of Physics is a spectacular example.) Laurie Fitzgerald says that

even scientists, who as a group pride themselves on their ability to maintain objectivity, have found it enormously difficult to give up the sense of certainty, constancy and control once derived from the view of reality formed by the ‘old’ science.

Modern scientific perceptions of the universe have more in common with ancient Chinese philosophy than they have with Western scientific thought of the last several centuries. In the new science, everything is determined by perspective and relationships, not cause and effect.
Humans are intrinsically incapable of impartial observation of natural phenomena because they are natural phenomena.
Lynn Margulis reminds us

Independence is a political, not a scientific, term.

Atomic matter could not conceivably exist in the world of Newtonian mechanics. It took the new reality of quantum mechanics to show us the atomic level, where objects dissolve into wavelike patterns of probabilities and correlations. The new universe is a “complicated tissue of events, in which connections of different kinds alternate or overlap or combine and thereby determine the texture of the whole,” wrote Werner Heisenberg.
Neils Bohr told Einstein in their famous discourse that one cannot assume that the universe has separate and independent units; Bohr practically invented the modern scientific concept of the absolute connectivity of the universe.
Out of the collapse of the old science came the fluid, Daoist world of the new science. No more order, rationality or equilibrium (except at death).
Science recognized four fundamental forces at work in the universe:

  • Gravity. This is the dominating force in the universe.
  • Electromagnetism. This is what works at a planetary level. Most of our planet’s energy is supplied to us by our sun in this way.
  • Weak nuclear force. This works at the atomic level.
  • Strong nuclear force. This also works at the atomic level.

It was Einstein’s goal to put these four forces into one mathematical theory — the unified field theory.

New Age is Not New Science

Some of the key differences in the old scientific mindset and the new are outlined below. Cartesian thought is underlined. The new thinking appears after it.
Thought is a product of brain activity. In Santiago Cognition Theory, the brain is not necessary for mind to exist. Mind is the process of cognition, the process of life itself. As Maturana and Varela explain,

Consciousness is essentially a social function.

Most of the universe is dead.

We are but whirlpools in a river of ever-flowing water. We are not stuff that abides, but patterns that perpetuate themselves.
— Norbert Weiner, founder of cybernetics

Scientific descriptions are independent of the observer and the process of knowing. Epistemology is essential in the description of natural phenomena.

What we observe is not nature itself, but nature exposed to our method of questioning.” — Werner Heisenberg

We are separate from nature. According to Francisco Varela, et al, this “Cartesian anxiety” is a harmful construct:

A separate individual self is an illusion and to cling to this notion brings suffering and frustration.

The differences between the old and the new are essentially this: in classical mechanics the properties and behavior of the parts determine those of the whole, while in quantum mechanics the situation is reversed — study of the whole determines the behavior of the parts. Laurie Fitzgerald says

All ‘things’ are absolutely connected to each other and to the whole of which they are part. Units have no meaning in a chaotic system and, therefore, do not exist.

Mommy Earth and Me

It took years of forcible repression to replace people’s original conceptual framework of the world as a holistic system (a so-called “primitive superstition” even in recent memory) with the rational Cartesian one. Scientists were faced with the old universe they worked so hard to eradicate — and which had been exiled to the province of creative types and indigenous cultures at the fringes of Western civilization.
Scientists participate in the “conceptual infrastructure” of classical physics disintegrating as a result of evidence obtained in their investigations into the nature of the universe.
There had always been reactions against Cartesian-Newtonian thought in segments of the population, of course, but most were marginalized populations with little or no influence. The most famous antireductionistic and antimechanistic group was the Romantic Movement.
From Blake to Goethe to Kant, all fervently believed in the extremely ancient worldview of the planet and its creatures as a holistic living system. It was aptly expressed by a medieval alchemist, Basilius Valentinus, as well as any Kabbalist or Romantic:

The earth is not a dead body, but is inhabited by a spirit that is its life and soul. All created things, minerals included, draw their strength from the earth spirit. The spirit is life, it is nourished by the stars, and it gives nourishment to all the living things it shelters in its womb.

Modern Gaia Theory also echoes the ancient worldview, but uses the new science in its exploration of the mythos.
Dorion Sagan and Lynn Margulis call it “symbiosis as seen from space,” the holistic world as “the nexus and nest, the global life and environment, the planetary surface seen as body rather than place.”
Aldo Leopold coined the environmental and ecological scientist’s version about 20 years ago:

Land is not merely soil; it is a fountain of energy flowing through a circuit of soils, plants, and animals.