De Motu (Berkeley's essay)
Encyclopedia
De Motu is an essay written by George Berkeley
and published in 1721. Its full title is De Motu or The Principle and Nature of Motion and the Cause of the Communication of Motions. The essay was unsuccessfully submitted for a prize that had been offered by the Royal Academy of Sciences
at Paris
.
Berkeley rejected Sir Isaac Newton's absolute space
, time
and motion
. With this essay, Berkeley is considered to be the "precursor of Mach
and Einstein
."
things themselves, not with abstract
terms. The effects that are felt on our senses should be noticed. The causes of these effects are rationally inferred and are occult
qualities.
Gravity and force
are examples of occult qualities. But they can be useful terms. Gravity can designate concrete bodies in motion and force can designate the concrete effort of resisting. However, they should not be used abstractly, separate from concrete, individual things. If no change occurs and there is no effect, then there is no force. Force, gravity, and attraction are mathematical, hypothetical abstractions and they are not found in nature as physical qualities. The parallelogram
of composite forces is not a physical quality. It is mathematical. Attempts to explain the cause and origin of motion are abstract and obscure. They are not particular and determinate assertions. Such attempts try to explain the unknown by something that is even more unknown.
s, however, are known to cause motion. Such minds are particular, individual causes that are parts of the primary, universal cause of motion.
Bodies are passive, not active. They merely persist indifferently in their states, whether of impelled motion or of rest. Action
and reaction
are only mathematical hypotheses, not physical qualities. It is useful to refer to action and reaction when demonstrating mechanics, but they are not causes of motion.
We personally experience within ourselves a cause of our bodily motion. It is called soul
, mind, or spirit
. But, we do not experience a cause of motions inside of other bodies. The ultimate cause of the motion of all bodies is the mind of God
. This is known through metaphysics
and theology
.
Natural science is limited to experiment
s and mechanics
, but it assumes that God was the prime source of motion. The laws of motion, not the cause of motion, are established by natural science. Physicists explain and understand phenomena by showing how they agree with the laws of motion. Fictional, abstract, general terms such as force, action, and reaction are used in theories, formulas, and computations. These cannot be found in bodies.
Through our senses, we actually experience only the effects of moving or resting bodies. The natural scientist is concerned with experiments, laws of motion, mechanical principles, and rational deduction from those principles. The principle and cause of motion itself is a metaphysical, theological, and moral
concern.
and time
. It should not be analyzed into abstract ideas such as movement, velocity
, and force. Mathematical considerations of spatial and temporal infinitesimal
s lead to paradox
es. Motion should not be equated with the cause of motion. To say that the quantity of motion is always conserved is to confuse motion itself with the force that causes motion. The force of the cause of motion is conserved. Motion is not an internal, living force in things. It is a lifeless, indifferent effect.
. They presuppose a relationship to some other body through which they are determined. For a wider view, it would be useful to consider motion relative to the fixed star
s, which would be considered as being at rest, instead of to absolute space. Just as we cannot know absolute space, we cannot know whether the whole universe is at rest or is moving uniformly in a direction.
To determine the true nature of motion, we must follow three rules: (1) distinguish mathematical hypotheses from the nature of things; (2) beware of abstractions; (3) consider motion as sensible or imaginable and be content with relative measures.
George Berkeley
George Berkeley , also known as Bishop Berkeley , was an Irish philosopher whose primary achievement was the advancement of a theory he called "immaterialism"...
and published in 1721. Its full title is De Motu or The Principle and Nature of Motion and the Cause of the Communication of Motions. The essay was unsuccessfully submitted for a prize that had been offered by the Royal Academy of Sciences
French Academy of Sciences
The French Academy of Sciences is a learned society, founded in 1666 by Louis XIV at the suggestion of Jean-Baptiste Colbert, to encourage and protect the spirit of French scientific research...
at Paris
Paris
Paris is the capital and largest city in France, situated on the river Seine, in northern France, at the heart of the Île-de-France region...
.
Berkeley rejected Sir Isaac Newton's absolute space
Space
Space is the boundless, three-dimensional extent in which objects and events occur and have relative position and direction. Physical space is often conceived in three linear dimensions, although modern physicists usually consider it, with time, to be part of a boundless four-dimensional continuum...
, time
Time
Time is a part of the measuring system used to sequence events, to compare the durations of events and the intervals between them, and to quantify rates of change such as the motions of objects....
and motion
Motion (physics)
In physics, motion is a change in position of an object with respect to time. Change in action is the result of an unbalanced force. Motion is typically described in terms of velocity, acceleration, displacement and time . An object's velocity cannot change unless it is acted upon by a force, as...
. With this essay, Berkeley is considered to be the "precursor of Mach
Ernst Mach
Ernst Mach was an Austrian physicist and philosopher, noted for his contributions to physics such as the Mach number and the study of shock waves...
and Einstein
Albert Einstein
Albert Einstein was a German-born theoretical physicist who developed the theory of general relativity, effecting a revolution in physics. For this achievement, Einstein is often regarded as the father of modern physics and one of the most prolific intellects in human history...
."
Concrete and Abstract Motion
We must pay attention to facts regarding things and their nature, not to words or to someone's authority. The mind should be concerned with particular and concreteConcrete
Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
things themselves, not with abstract
Abstract object
An abstract object is an object which does not exist at any particular time or place, but rather exists as a type of thing . In philosophy, an important distinction is whether an object is considered abstract or concrete. Abstract objects are sometimes called abstracta An abstract object is an...
terms. The effects that are felt on our senses should be noticed. The causes of these effects are rationally inferred and are occult
Occult
The word occult comes from the Latin word occultus , referring to "knowledge of the hidden". In the medical sense it is used to refer to a structure or process that is hidden, e.g...
qualities.
Gravity and force
Force
In physics, a force is any influence that causes an object to undergo a change in speed, a change in direction, or a change in shape. In other words, a force is that which can cause an object with mass to change its velocity , i.e., to accelerate, or which can cause a flexible object to deform...
are examples of occult qualities. But they can be useful terms. Gravity can designate concrete bodies in motion and force can designate the concrete effort of resisting. However, they should not be used abstractly, separate from concrete, individual things. If no change occurs and there is no effect, then there is no force. Force, gravity, and attraction are mathematical, hypothetical abstractions and they are not found in nature as physical qualities. The parallelogram
Parallelogram
In Euclidean geometry, a parallelogram is a convex quadrilateral with two pairs of parallel sides. The opposite or facing sides of a parallelogram are of equal length and the opposite angles of a parallelogram are of equal measure...
of composite forces is not a physical quality. It is mathematical. Attempts to explain the cause and origin of motion are abstract and obscure. They are not particular and determinate assertions. Such attempts try to explain the unknown by something that is even more unknown.
Principles or Causes of Motion
Bodies are not known to contain, within themselves, forces that cause motion. MindMind
The concept of mind is understood in many different ways by many different traditions, ranging from panpsychism and animism to traditional and organized religious views, as well as secular and materialist philosophies. Most agree that minds are constituted by conscious experience and intelligent...
s, however, are known to cause motion. Such minds are particular, individual causes that are parts of the primary, universal cause of motion.
Bodies are passive, not active. They merely persist indifferently in their states, whether of impelled motion or of rest. Action
Action (physics)
In physics, action is an attribute of the dynamics of a physical system. It is a mathematical functional which takes the trajectory, also called path or history, of the system as its argument and has a real number as its result. Action has the dimension of energy × time, and its unit is...
and reaction
Reaction (physics)
The third of Newton's laws of motion of classical mechanics states that forces always occur in pairs. Every action is accompanied by a reaction of equal magnitude but opposite direction. This principle is commonly known in the Latin language as actio et reactio. The attribution of which of the two...
are only mathematical hypotheses, not physical qualities. It is useful to refer to action and reaction when demonstrating mechanics, but they are not causes of motion.
We personally experience within ourselves a cause of our bodily motion. It is called soul
Soul
A soul in certain spiritual, philosophical, and psychological traditions is the incorporeal essence of a person or living thing or object. Many philosophical and spiritual systems teach that humans have souls, and others teach that all living things and even inanimate objects have souls. The...
, mind, or spirit
Spirit
The English word spirit has many differing meanings and connotations, most of them relating to a non-corporeal substance contrasted with the material body.The spirit of a living thing usually refers to or explains its consciousness.The notions of a person's "spirit" and "soul" often also overlap,...
. But, we do not experience a cause of motions inside of other bodies. The ultimate cause of the motion of all bodies is the mind of God
God
God is the English name given to a singular being in theistic and deistic religions who is either the sole deity in monotheism, or a single deity in polytheism....
. This is known through metaphysics
Metaphysics
Metaphysics is a branch of philosophy concerned with explaining the fundamental nature of being and the world, although the term is not easily defined. Traditionally, metaphysics attempts to answer two basic questions in the broadest possible terms:...
and theology
Theology
Theology is the systematic and rational study of religion and its influences and of the nature of religious truths, or the learned profession acquired by completing specialized training in religious studies, usually at a university or school of divinity or seminary.-Definition:Augustine of Hippo...
.
Natural science is limited to experiment
Experiment
An experiment is a methodical procedure carried out with the goal of verifying, falsifying, or establishing the validity of a hypothesis. Experiments vary greatly in their goal and scale, but always rely on repeatable procedure and logical analysis of the results...
s and mechanics
Mechanics
Mechanics is the branch of physics concerned with the behavior of physical bodies when subjected to forces or displacements, and the subsequent effects of the bodies on their environment....
, but it assumes that God was the prime source of motion. The laws of motion, not the cause of motion, are established by natural science. Physicists explain and understand phenomena by showing how they agree with the laws of motion. Fictional, abstract, general terms such as force, action, and reaction are used in theories, formulas, and computations. These cannot be found in bodies.
Through our senses, we actually experience only the effects of moving or resting bodies. The natural scientist is concerned with experiments, laws of motion, mechanical principles, and rational deduction from those principles. The principle and cause of motion itself is a metaphysical, theological, and moral
Moral
A moral is a message conveyed or a lesson to be learned from a story or event. The moral may be left to the hearer, reader or viewer to determine for themselves, or may be explicitly encapsulated in a maxim...
concern.
Nature of Motion
Motion should not be considered as an abstraction, separated from spaceSpace
Space is the boundless, three-dimensional extent in which objects and events occur and have relative position and direction. Physical space is often conceived in three linear dimensions, although modern physicists usually consider it, with time, to be part of a boundless four-dimensional continuum...
and time
Time
Time is a part of the measuring system used to sequence events, to compare the durations of events and the intervals between them, and to quantify rates of change such as the motions of objects....
. It should not be analyzed into abstract ideas such as movement, velocity
Velocity
In physics, velocity is speed in a given direction. Speed describes only how fast an object is moving, whereas velocity gives both the speed and direction of the object's motion. To have a constant velocity, an object must have a constant speed and motion in a constant direction. Constant ...
, and force. Mathematical considerations of spatial and temporal infinitesimal
Infinitesimal
Infinitesimals have been used to express the idea of objects so small that there is no way to see them or to measure them. The word infinitesimal comes from a 17th century Modern Latin coinage infinitesimus, which originally referred to the "infinite-th" item in a series.In common speech, an...
s lead to paradox
Paradox
Similar to Circular reasoning, A paradox is a seemingly true statement or group of statements that lead to a contradiction or a situation which seems to defy logic or intuition...
es. Motion should not be equated with the cause of motion. To say that the quantity of motion is always conserved is to confuse motion itself with the force that causes motion. The force of the cause of motion is conserved. Motion is not an internal, living force in things. It is a lifeless, indifferent effect.
Motion in space
Absolute space contains no bodies. But, as such, it would not be observable. Nothing is denoted by the words "absolute space." Motion and space are relativeRelative
-General use:*Kinship, the principle binding the most basic social units society. If two people are connected by circumstances of birth, they are said to be relatives-Philosophy:...
. They presuppose a relationship to some other body through which they are determined. For a wider view, it would be useful to consider motion relative to the fixed star
Fixed star
The fixed stars are celestial objects that do not seem to move in relation to the other stars of the night sky. Hence, a fixed star is any star except for the Sun. A nebula or other starlike object may also be called a fixed star. People in many cultures have imagined that the stars form pictures...
s, which would be considered as being at rest, instead of to absolute space. Just as we cannot know absolute space, we cannot know whether the whole universe is at rest or is moving uniformly in a direction.
To determine the true nature of motion, we must follow three rules: (1) distinguish mathematical hypotheses from the nature of things; (2) beware of abstractions; (3) consider motion as sensible or imaginable and be content with relative measures.