The Essence of Life
A Scientific Philosophical Perspective
The Philosophy of Biology
Part II On the Relation Between the Philosophy of Biology and Biology
To gain some initial understanding of the essence of philosophy of biology, let us look, first, at its relation to biology, and then to general philosophy.
Biology is the science that studies the phenomena of life, in its all numerous, diversified manifestations.
Biologists study animals and plants − their complex structures and functions, and the complicated relations among them and between them and their environments.
These features of the living organisms are the focus of the biological research; but they do not constitute the essence of the research.
Biologists seek to clarify and understand the nature of the structures and processes of life, i.e., to know them and their underlying causes.
In revealing the nature of life, biologists produce biological knowledge. However, they are hardly concerned with the knowledge itself − they do not, in general, examine and analyze its meanings and implications, nor the processes by which it is produced and obtained.
This study is the essence of the philosophy of biology.
Identifying and analyzing fundamental premises of the biological research, defining its central concepts, examining its methods, clarifying central ideas and integrating them into a coherent scientific discipline − all these are among the main objectives of the philosophy of biology.
The following brief presentation of two issues in biology, a study of the nature of a biological species and a study of a biological process, illustrating the difference between biology and the philosophy of biology, may provide a somewhat clearer idea of the essence of the philosophy of biology.
In the late 1860s, Armand David, a French missionary Catholic priest, was sent to China to establish Catholic schools. David was also an enthusiastic naturalist who collected plants and animals.
David’s description of “the black and white bear” that he discovered in China was the first scientific documentation of the giant panda, one of the most adorable, well-known animals today, which had aroused great interest among researchers, not only because it was a new species to science, but also for its unique characters.
A careful study of the giant panda’s anatomy, the structure of its various organs and systems (skeleton and muscles, respiratory and digestion systems, etc.), reveals that although the panda shares many features with the bears (the family Ursidae), it also has some unique characteristics, such as the structure of its molar teeth and a small extension of a bone in the paw that looks like an extra sixth finger, which functions as an opposable thumb.
The habits of the panda, like its diet, which is mainly bamboo, are also very different from those of the carnivorous bears.
These differences led to a long-standing controversy among researchers about the panda’s proper phylogenetic position: does it belong to the ursids (bears), despite the differences between them, or whether it is more closely related to the procyonids (raccoons), and perhaps it should be classified in its own family?
The issue of the evolution of the panda has also aroused much curiosity. The researchers ask, for example, how did the panda’s “thumb” develop, what were the causes that led to the adaptation of this mammal, which has a carnivore’s digestive system, to its unique diet consisting almost exclusively on bamboo, or, as Dwight Davis asks in his comprehensive monograph on the panda’s anatomy, what was “the raw material on which natural selection acted?”
All these questions − about the panda’s body structure, its lifestyle, taxonomic position and evolution, and numerous other questions, including, for instance, how to ensure the survival of this lovable species (which is in danger of extinction and the symbol of the WWF, the World Wildlife Fund) − are biological questions, topics that are studied in the various areas of biology.
By contrast, questions about, for example:
Natural selection − such as, is it a fact or a theory, what is its importance to biology in general and to the study of evolution in particular, what are the units of selection, i.e., the biological entities that are subjected to natural selection (the species or the population, the individual organism, its cells or its genes) − not only in the context of a particular species, such as the giant panda, but in general;
Classification − e.g., what is it needed for, what are the best methods of classification and what are they based on;
The concept of ‘biological species’ − e.g., what is a biological species and what are the criteria for defining a species;
Biodiversity − for example, why is it important to protect endangered species and what are the best ways to conserve biodiversity;
The essence of life − e.g., is there a fundamental character common to all living things, animals and plants, such as, for instance, the panda and the bamboo, which distinguishes them from the inanimate;
All these questions are in the field of the philosophy of biology.
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Heredity, the fact that there is a resemblance between parents and their offspring, was known to humans from the dawn of history. However, the nature of this phenomenon and its underlying causes had been a mystery throughout the ages. It was not until the twentieth century that it has become clear how the parent’s traits are transmitted to offspring.
Many scientists were working to unravel the enigma of heredity.
Among the most well-known of them are:
Gregor Mendel, who discovered by cross breeding experiments with garden peas, the principles (known as Mendel’s laws) according to which some specific traits of the plants are transmitted from one generation to another;
August Weismann, who developed a theory that the process of heredity (in multicellular organisms) occurs by a transmission of hereditary material from the parents’ germ cells to their offspring’s germ cells;
Theodor Boveri and Walter Sutton, who independently suggested that chromosomes carry the hereditary material, a hypothesis that was later established by Thomas Hunt Morgan through his experiments with the fruit fly;
George Beadle and Edward Tatum, whose experiments with bread mold led to the clarification of the relation between genes, the hereditary factors that are carried on the chromosomes, and proteins;
Oswald Avery, who worked with bacteria that causes pneumonia and demonstrated that DNA is the hereditary material;
Rosalind Franklin, Maurice Wilkins, James Watson and Francis Crick, who discovered in 1953 the molecular structure of DNA, the structure of the double helix.
In the following years, intense research by many other scientists led to the clarification of the molecular mechanisms by which the genetic material is replicated and transmitted from one generation to the next.
It seemed that the riddle of heredity was fully deciphered.
However, and largely as a result of the new discoveries, many new questions have been raised concerning the subject of heredity.
Some of these questions are in the area of the philosophy of biology.
I will briefly mention some of them:
Many scientists, among them Watson and Crick, argued that the identification of the genetic factors and their way of action would lead to deciphering the “secret of life”. Has this expectation been fulfilled? Are the genetic mechanisms discovered by biological research the ones that underlie the phenomenon of life in all its complexity, and do they explain life processes as a whole?
Can the genetic program, i.e., the genetic information stored in the nucleotide (the basic unit of DNA) sequences, explain in principle, as many biologists believe, the development of living organisms with all their complex − morphological, functional, behavioral − characters?
What is the meaning of such terms as ‘genetic program’ or ‘genetic code’? Is the use of these terms compatible with their real meaning, and how does this use affect biological research, particularly in the fields of genetics and developmental biology?
Why do biologists need terms taken from the realm of consciousness, such as ‘program’ and ‘code’, even though biology has demonstrated beyond any reasonable doubt that life processes are nothing but physicochemical processes, i.e., physical and chemical reactions that are governed by the same natural laws as inanimate matter? And if there is a difference between animate and inanimate matter − what is this difference?
What is the nature of the relationship between heredity and development, at the level of the individual (the development of a single organism from its germ cells) and at the level of the species (evolutionary development)?
In recent decades there has been a growing understanding of the nature of inheritance systems that are not genetic, namely, epigenetic and cultural inheritance systems. In what ways does our understanding of these additional inheritance systems affect our perception of heredity and development?
Is it possible that our current view of heredity will change dramatically in the future? And if so, are we condemned to live in constant doubt regarding our knowledge and understanding of the phenomenon of life?
All these questions deal with biological knowledge − with its contents (the central ideas and concepts that constitute its foundation), with the ways by which it is acquired (the methods of biological research), and the ways by which it is consolidated into a coherent body of knowledge and integrated with existing knowledge.
These questions are included in the field of the philosophy of biology; but are they philosophical questions?
What is the relation between the philosophy of biology and philosophy?