Great Scientists and Thinkers That Reevaluated the Way We Think

Over the years, great scientists and thinkers have reevaluated and reworked the way we think about the natural world.  From Aristotle to Newton to Darwin and Einstein, the great modern scientists are constantly trying to find better and more accurate ways to view the nature we have been born into.  The natural world as well has constantly changed throughout history, and as more new phenomena are discovered, scientists must try and develop new systems of natural perspective to understand and better comprehend the environment around us.  For modern natural science, however, there is no question that much of the radical new waves of thought have sprung out of the 18^th and 19^th century schools of thought.  Charles Darwin, among others, has been a significant influence on the way we perceive life and nature.  However, his theories, and that of others’ are constantly being modified even today—nature, much like science, continues to evolve and become more sophisticated.

            The Great Chain of Being is the Classical Greek concept, cited by later philosophers and scientists, including John Locke, which states that all living beings that are capable of existing do indeed exist.  The original Greek concept, developed primarily by Aristotle, expressed that living beings were scaled to perfection, from the simple to the intricate.  By way of this concept, classifications could be made between types of living beings; for example, one could separate a waterbug from a monkey, on the basis that the waterbug’s properties are simpler and the monkey’s much more complex.  The idea has been incorporated and integrated with the ideologies of Western Christianity—that God, whose perfect design for His Earth and Creation, had created a world that was fully interactive and cooperative, that nature could not have existed any other way than it had, and that life on Earth was “gapless.”  The idea of the Great Chain of Being is somewhat dependent on the belief of a perfect creator, but it was a significant point of progress in discerning between life forms (p. 244).

            The idea of the “fixity of species” drew upon the foundations of the Great Chain of Being concept that it was God’s design alone that had created this seamless chain of life forms that all served their own purposes within the environment.  Proponents of the fixity of species believed that the life forms available and in existence on the Earth would remain unchanged through the end of time.  Again, much like the Great Chain of Being idea, the fixity of species idea was dependent on the foundations of Christianity, on the belief of a perfect Creator and the idea that God had made a set decision on the existence of life forms on this Earth.  Because God’s design was, according to Christians and proponents of this theory, perfect, there could be no change or alteration in the status of living beings.  However, as scientists and philosophers continued to discover new life forms, and as existing life forms gradually went extinct, many abandoned this theory in favor of a more adaptive theory that allowed for the evolution and change of species.  While the fixity of species theory depended highly on the belief of a Great Chain of Being and the Christian God, the origination and subsequent abandonment of the fixity of species theory marked a significant event in natural science—a dawning understanding of evolution (p. 246).

            Both the Great Chain of Being concept and the fixity of species theory were ideas that were heavily based in Western Christianity ideologies.  They encouraged people to integrate the Christian way of thought in their perspectives of the natural world.  However, as scientists began investigating the validity of these theories, they realized that the theories were too rigid—they did not allow the evolution, origination and extinction of species.  Scientists realized that the theories would not hold up against the real-life observations in the natural world.  They were abandoned by many, finally, and more importantly, paved the way for the widely-accepted scientific perspective of the natural world we utilize today (p. 244-246).

            Carl Linnaeus was an influential scientist who revolutionized the way scientists studied plants.  He was a key figure in making known the sexuality of plants and how the sexes of plants was integral in plant reproduction.  He drew upon the ideas of Nehemiah Grew and Rudolph Camerarius—however, Linnaeus’ idea paved the way for classifications of species through his observations on the different reproductive systems of plants.  Furthermore, his ideas explicitly challenged the fixity of species theory in that his idea was inherently “artificial,” created out of observations of the workings of the natural world, not a comprehensive description of plant properties (p. 248-249, 253).

            The Theory of Preformation was a direct challenge to the Descartes’ theory that mechanical laws dictated the growth of living beings.  The theory was offered by Malebranche, who believed that while Descartes was correct in pointing out the importance of mechanical laws in regards to the growth of life, being dependent on mechanical laws to explain growth was not sufficient in his eyes.  Malebranche believed that direction, purpose, was necessary for growth to happen—in this case, he was referring to an embryo.  Malebranche stated that embryos were not merely formless masses that grew in adherence to mechanical laws, but had a predestined “form” that they would adhere to in order to attain the properties of the species that propagated it (p. 256).

            However, while Malebranche’s theory pointed out a clear observation on life growth, his theory of preformation was challenged in several ways.  One of the most significant blows to Malebranche’s theory was the work of Abraham Trembley, who discovered that by observing a freshwater polyp, an organism could be cut in two and still produce a complete adult form.  The discovery suggested that there was no need for a predetermined adult form to exist for proper growth to occur.  Furthermore, Buffon, who had been an opponent of Linnaeus’, observed within an embryo that the adult form was not readily apparent until later stages of development.  He also observed that the subsequent offspring of two living beings represented the properties of both parents (p. 257).

            The theory of Epigenesis was another way of explaining the growth of life and embryos.  The epigenesist theory stated that the embryo had no predetermined form, that it was merely a shapeless mass, and only grew in adherence to the mechanical laws that acted upon it (p. 257).

            The problem with the theory of Epigenesis was that it could not explain the integrated and cooperating properties of the body that would form from the growth of the embryo.  The theory was thought to have merely complicated the concept of growth without adequately explaining the mechanics behind it (p. 258).

            The Haller-Wolff debate was a debate between Albercht Haller and Caspar Wolff, a preformationist and an epigeneticst, respectively.  The two scientific thinkers examined both sides of the argument and conducted experiments to settle the clash of ideologies.  The debate was notable because two unbiased and open-minded thinkers tackled the problem of explaining growth.  What resulted was a slow and gradual investigation of real-life occurrences and phenomena—in the end, the two thinkers would remain  steadfast to their beliefs, but would understand the valid points the other side of the argument would make (p. 258-259).

            Kant’s teleomechanical approach was a supporting argument of the theory of epigenesist.  Kant’s beliefs were very influential within his home country of Germany.  He believed that organisms, while adhering to mechanical laws, were not build as “machines,” specifically—rather, he noted, that while organisms are affected by mechanical laws, it is impossible to discern in an organism the purposes of the organism solely through observation of the mechanical laws.  Instead, one must observe the organism empirically, and only until the organism is seen as a whole can the purpose be determined or given (p. 261-262).

            Linnaeus and fellow scientist Georges Cuvier were two scientific thinkers that greatly influenced the way people viewed the natural world and developed taxonomies that paved the way for the classification of species years later.  Both Linnaeus and Cuvier would go on to develop systems that were highly influential for years to come.  While Linnaeus’ system depended on classifying organisms by their physical properties, Cuvier pointed out that, especially in regards to classification of animals, Linnaeus’ system was inadequate.  He noted that while Linnaeus’ system may have worked for the classification of plants, animals often exhibited similar physical characteristics, but did not really belong to the same class of organism.  Instead, Cuvier focused on the interaction of the nervous system to the “organs of motion” to classify animals.  Using this method, Cuvier developed a more accurate form of classification of animals (p. 355-357).