Introduction
There is a consensus in natural science that for all species to survive and reproduce for generations, there must be variation. This variation constitutes all morphological and biochemical characteristics that may be suited for adaptation in the environment. This principle that there should be variation in organisms is followed by the fact that these biochemical and morphological variations are heritable. Changes in the characteristics of organisms can be observed for many generations. These changes and adaptation to the environment are what drives the evolution of every species through passing the trait for each generation. Since these variations are heritable, then this process affects fitness. Fitness is the relative ability of a particular individual to survive and reproduce in a given environmental condition. Fitness constitutes the overall characteristics of an organism and as mentioned above, these characteristics are heritable. Therefore, heritable variation affects fitness.
Heritable variation affecting fitness is considered a core principle for the explanation of evolution. Changes through time in organisms through selection, mutation, and recombination must be heritable to affect the survival and reproduction of more fit organisms. There is no other way that evolution can be achieved but through heritable variation.
Charles Darwin extensively used this principle to forward his theory of evolution in his book The Origin of Species. According to Darwin, evolution takes place through the aid of natural selection wherein only the fittest survives. His argument follows that the environment dictates the changes in the morphological characteristic changes in a single species that enable it to better cope with the conditions surrounding it. If these changes in the characteristics are passed down to the following generations for the perpetuation of a particular species, then evolution takes place.
The Genetical Theory of Natural Selection
The close equality in the numbers of males and females in nature was considered one of the most controversial questions that R.A. Fisher tried to answer in his The Genetical Theory of Natural Selection. His work illustrated the mechanism where natural selection defines a population property such as sex ratio at the individual level.
Fisher argues that if in a natural population the number of males exceeds that of the females arising from the increased reproductive value in each female than in each male since each type imparts exactly 50 percent of the ancestry of future generations. This condition, according to Fisher, implies that the parents who are genetically programmed to generate females in surplus of the average of the population are therefore contributing a disproportionately large share in the gene pool. Moreover, the parents are also contributing genes for generating females excessively. The result will be a shift from the current imbalance towards 50 percent which according to Fisher’s argument is the equilibrium value.
Fisher’s argument was considered as the primary example of the concept called evolutionary stable strategy and aroused interest in the importance of parental expenditure in evolution. He was highly regarded in following works in biological phenomena such as those of Williams, Maynard, and Hamilton. In addition, his ideas provided the basis for the application of natural selection for the evolution operating inside populations.
The above research areas serve as biological laws in maintaining equilibrium inside populations. The fact that all species achieve some level of stability during reproduction and survival in the course of their evolution implies the presence of these biological laws. Without such propositions by Fisher, Williams, Maynard, and Hamilton regarding evolution inside populations, most species would have not lasted for several generations.
Physicalism is a philosophical argument
Physicalism is a philosophical argument forwarded by Otto Neurath claiming that everything exists as it is and there is nothing more than its physical characteristics and thus there are no other categories of existence beyond physical things. According to its proponent, the language of physics is the sole language of every scientific theory of knowledge. This implies that physicalism covers the existence of matter, energy, space, time, and other entities recognized by physics.
Vitalism is a philosophical stance that maintains that the functions of every living organism are derived from a vital principle that is separate from the physical or chemical elements. It asserts that the purpose and functions of living organisms cannot be explained or governed alone by physics and chemistry. Instead, vitalism instills that life is partly self-determining.
Dualism is a philosophical view that two fundamental sides or concepts exist in the world. For every entity, there is an opposite element. Examples are good and evil, male and female, and light and darkness.
The modern scientific world would not favor vitalism to explain the function of life. Due to advances in biochemical researches, more and more complex mechanisms are being exposed to explain how life started and proliferates. To suggest that it is best to leave the meaning of life to the organism is not at any level scientific.
To some extent, dualism may be accepted by the scientific world due to the presence of two sides in every species. However, the applicability stops there and the details of biochemical processes cannot be explained by dualism. There is more to the rigid view of dualism to the dynamic and ever-changing mechanisms of the living world.
Creation of an intelligent being
William Paley, in his book published in 1802 titled Natural Theology, or Evidence of the Existence and Attributes of the Deity Collected from the Appearances of Nature, argued that everything has its creator the way stones and watch require a person to bring these things into existence. Following this reasoning, Paley applied this to more complex things such as plants and animals, noting their highly specialized and intricate structures for survival and adaptation. Such organisms, according to him, like a watch require an intelligent designer since these cannot simply crop up in the middle of nowhere. Therefore, he argued that the natural world is a creation of an intelligent being and that being is God.
The creation shows the nature of its creator. According to Paley, God meticulously crafted all forms of life from the most complex to the simplest including their unique characteristics such as wings and antennae. He added that since humans are highly complex compared to most organisms it means that God places more importance or care for humanity.
Hume’s critique of the design argument is based on the fact that the analogy is not appropriate. For example, there is little value, according to Hume, in comparing watches and the whole universe. Hume expounds that there is a weak analogy when object A is compared with object B based on a certain degree of similarity. There is only a little degree of similarity between the watch and the universe and that is the apparent complexity in the two but it is not sufficient to place the two in the same category to conclude.
Paley’s design argument can be considered as an abductive argument which Hume classifies as a weak analogy. Therefore, Paley’s design argument using the watchmaker and the universe is vulnerable to Hume’s critique.
Perfect and imperfect adaptation
Perfect and imperfect adaptation provides the ability of a particular organism to change its characteristics for its survival and reproduction. Perfect adaptation would lead to better fitness for a particular organism and would entail the proliferation of its species while imperfect adaptation results in inappropriate changes that can lead to detrimental effects on the survival and reproduction of a species.
According to Charles Darwin, natural selection occurs randomly in nature to favor those organisms that have developed appropriate morphological or biochemical properties for better adaptation in the environment. The genetic variation that is produced is selected to leave the fittest individual for the perpetuation of the species.
These two principles depart from the contentions of creationism. Creationism claims that God created all living organisms including the physical world where organisms exist. The fate and the very functions of all organisms are according to the will of God. Every organism serves a particular purpose in life. They are equally important to the eyes of their creator.
Perfect and imperfect adaptation is contradictory to the will of God for creationists since every organism is left on its own to survive. A species must change to enable it to last as long as possible which is not consistent with creationism since God created every life as they are and are expected to be fruitful in God’s eyes.
Natural selection is a random occurrence for the survival of those benefiting from useful changes in morphology. God’s creations are not of random order and importance since these are created equally in God’s eyes. God, according to creationism, made these organisms to serve their purpose in life. Everything has a role, an idea that is opposite to the randomness of natural selection. In other words, natural selection differs largely from the view of creationism.
Demarcation as a core problem
Karl Popper noted the role of demarcation as a core problem in scientific philosophy. As a solution to problems confronting thinkers of his time, he proposed falsification as a method of establishing the scientific merit of a particular theory in place of the then deliberated verification method. He argued that if a particular theory can be falsified then that theory can be considered scientific; however, if it can’t falsify, it will not be scientific. According to Popper, falsifiability is a characteristic of principles and theories which is classified as neutral. He used this as a demarcation criterion as a basis for the establishment of falsifiable theories against the non-falsifiable theories.
The weaknesses of Popper’s demarcation argument are encountered in the fact that even non-falsifiable statements are also useful in most scientific theories. Another is that Popper’s demarcation criterion would be dependent on the interpretation or relative to an individual considering the properties of a statement. In other words, Popper’s methodology is can be purely subjective and not objective. And lastly, his demarcation criterion if used would be impractical since there are not many important scientific theories that are in one way or another characterized by a level of irregularities or anomalies.
Karl Popper’s demarcation criterion can be used to assess the validity of creationist theories although in a limited level only. Accordingly, creationism would be non-falsifiable since there is no way that its principles can be tested; for example, the event of creation. This would mean that creationism is unscientific; however, this is purely subjective since no particular information can be discussed in this manner. The nature and existence of a Creator cannot be tested in a laboratory experiment. Nonetheless, the absence of a Creator cannot be also proven in the same way. Therefore, Popper’s demarcation criterion can never be aptly used.