The question of whether a human being qualifies as matter may seem philosophical, but the scientific answer is purely physical and biological. Matter is defined as any substance that possesses mass and occupies space (volume). From the perspective of physics and chemistry, the human body definitively meets this criterion. A person’s physical existence is rooted in the elements and energy that constitute the material world.
The Physical Definition of Matter
Matter is characterized by two universal properties: mass and volume. Mass measures the amount of substance in an object, reflecting its inertia or resistance to motion, typically quantified in kilograms. Volume is the three-dimensional space that substance occupies.
A human body exhibits both characteristics. We can be weighed, demonstrating measurable mass. A person displaces air and water and cannot occupy the same location as another object, confirming the property of occupying space. The body’s density, the relationship between its mass and volume, provides further evidence of its material nature.
The Essential Elements of Human Composition
The proof that humans are matter lies in our atomic composition. Approximately 99% of the body’s mass is composed of six elements: Oxygen, Carbon, Hydrogen, Nitrogen, Calcium, and Phosphorus. These elements form the molecular building blocks of all biological structures, including cells, tissues, and organs.
Oxygen is the most abundant element by mass (about 65%), primarily due to the high water content of cells. Water (H2O) acts as the main solvent necessary for nearly all chemical reactions. Carbon is the second most common element (roughly 18% of mass) and is the foundational atom for all organic chemistry. Because it can form four bonds, carbon creates the stable, complex backbones of carbohydrates, fats, proteins, and nucleic acids.
Hydrogen accounts for about 10% of the body’s mass, found in water molecules and organic compounds. Nitrogen makes up approximately 3.2% of body mass. This element is a fundamental component of all proteins and is integral to the nitrogenous bases that form the genetic code in DNA and RNA. Calcium provides structural rigidity in bones and teeth, while Phosphorus is incorporated into the energy molecule adenosine triphosphate (ATP).
Energy Flow and the Dynamic Nature of Living Matter
While a rock and a human are both composed of matter, human matter is dynamic and constantly engaged in energy exchange. The processes that sustain life are collectively known as metabolism, the sum of all chemical reactions occurring within the body. Metabolism is divided into two continuous processes: anabolism and catabolism.
Catabolism involves the breakdown of larger, complex molecules (like ingested food) into smaller, simpler ones. These reactions release energy stored in chemical bonds, which the cell captures. This released energy is used to synthesize adenosine triphosphate (ATP), often described as the cell’s energy currency.
Anabolism utilizes the energy derived from catabolism to construct complex molecules from smaller building blocks. Examples include synthesizing new proteins or replicating DNA strands for cell division. Anabolic reactions require energy input to create new cellular components and maintain existing structures. This constant, regulated cycling between catabolism and anabolism defines living matter and requires a continuous flow of energy to maintain organization.
The Scientific Answer to Human Existence
Science confirms that humans are matter, based on our physical properties and chemical makeup. We are assemblies of atoms, predominantly Oxygen, Carbon, Hydrogen, and Nitrogen, arranged into complex organic molecules. The defining quality of human existence is the extreme complexity of how our matter is organized and maintained, not the presence of a non-material component.
The continuous energy flow through metabolism prevents the body from degrading into disorganization, the natural tendency of non-living matter. This sustained, highly organized structure separates living human matter from inert matter. Therefore, a human being is a highly complex, dynamic form of organized matter, perpetually converting energy to sustain its intricate physical structure.
These elements form the molecular building blocks of all biological structures, including cells, tissues, and organs. Oxygen is the most abundant element by mass, comprising about 65% of the body, primarily because of the high water content of cells. Water, or H2O, acts as the main solvent in the body, which is necessary for nearly all chemical reactions. Carbon is the second most common element at roughly 18% of the mass, and it is the foundational atom for all organic chemistry.
Because it can form four bonds, carbon creates the stable, complex backbones of carbohydrates, fats, proteins, and nucleic acids. Hydrogen accounts for about 10% of the body’s mass, found both in water molecules and in every organic compound. Nitrogen constitutes a smaller but still significant portion, making up approximately 3.2% of body mass.
This element is a fundamental component of all proteins and is integral to the nitrogenous bases that form the genetic code in DNA and RNA. Calcium and Phosphorus are also present in substantial amounts, where Calcium provides structural rigidity in bones and teeth, and Phosphorus is incorporated into the energy molecule adenosine triphosphate (ATP).