The world of the ancient Greeks was one of burgeoning intellectual inquiry and was the cradle for some of the greatest minds in Hesperian thought. Within this vibrant, intellectual milieu there were none more luminary academic figures than Plato and his student Aristotle. These two revolutionary thinkers were predominantly responsible for the indoctrination of metaphysical inquiry in the western world. Though there conceptualisations of reality fundamentally differed, their mode of inquiry fostered the then nascent fields of mathematics, biology, zoology, meteorology and chemistry and provided future scholars with the practicalities for future discoveries. It is Aristotle's and Plato's contrasting views of reality and the impacts of these conceptual differences on their formations of scientific knowledge, that provides the raison d'tre for this inquiry.
For Plato what was ultimately real was the notion or concepts of things. He decreed that what we see in the physical world are merely abstract representations of universal concepts. Thus, Plato believed, that to truly understand reality one must transcend the physical reality into the world of ideas which is understood as Platonic Realism. Plato's main idea of the true nature of reality centres on the idea that abstract instances of universals are what creates the physical reality and that one cannot sensually perceive these universals as they have no spatial or temporal properties. He argued that all things have a universal form, such as a book, that exists outside of the physical book of which we can sensual perceive. We can look at a book but we can also study the form or the concept of the book thus giving us the particular book and the universal form of the book, Plato taught. Plato rested on the principles of one-over-many, self-predication and non-self-partaking to explain the existence of universals. These principles culminate in the realisation of platonic realism, and are the foundational pillars for the platonic world of forms, and Plato's conception of reality.
For Aristotle what constituted ultimate reality was not entirely different from that of Platonic Realism. Aristotle believed that what comprised ultimate reality was instantiated universals' whereas Plato believed in uninstantiated universals'. Thus Aristotle thought that the universal form of an object is not detached from the existing object but rather used as a predication for the existence of the object. Aristotle believed that the form of the aforementioned book exists within the book not in a mystical platonic world of forms. If some universal can not be predicated to an object that exists at some period of time then, for Aristotle, it does not exist. Justification of this concept employs the Eleatic principle; that those items we are ontologically committed to are causally effectual. For Aristotle the idea that there is a world of forms that is uninstantiated implied to him the idea of infinite regression. He explained this criticism with the use of the third man argument', which suggests that these principles of platonic realism are self-contradictory and ultimately leads one on an infinite quest to discover the origins of the platonic universal. For Aristotle what was ultimately real were instances that were actualised with instances that contained potentiality he deemed to be only half real.
Because of Plato's belief that reality was contained in the elegant explanations that mathematics could provide he was an exponent of the theoretical sciences. Plato's belief in the Pythagorean idea that the world could be explained through mathematics and geometry, naturally led him to reduce the importance of careful observation, like that of the natural sciences, and to emphasize the analytical, mathematical approach. The diversity of the material world is, according to Plato, the dissipated appearance of the eternal Ideas which range beyond sense and opinion. This notion provided Plato with the basis of his belief that to understand what is ultimately real one must use the notional science of mathematics rather than the natural sciences.
Plato's conception of science was fundamentally different from that of Aristotle's as Aristotle held that to achieve understanding of ultimate reality was to discover the universal that was encompassed in the objects that we experience in our physical reality. Because of Aristotle's rejection of the world of forms, his scientific enquires focused primarily on the natural sciences such as biology, zoology and meteorology. Aristotelian ideas of reality provided a new mode of demonstrative science for arriving at new scientific knowledge known as syllogistic or modal reasoning, which indoctrinated logical reasoning into the sciences. This form of reasoning involves understanding new truths by fashioning them from existing principles. In other words, deducing what we do not know from what we do. This form of reasoning, Aristotle suggests, would be the process one would undertake to understand what meteorological conditions are the inevitable constituents of rain. For Aristotle it is not enough to know that it rains, one must know how rain can exist. Aristotle proposed four different explanatory principles to arrive at a conclusion of why an instance exists. They are the material, formal, efficient and final cause and for Aristotle any explanation that includes all four causes completely captures the significance and reality of the instance itself.
Aristotle postulated that what scientifically constituted ultimate reality was comprised of five elements which were perfect mixtures of properties: fire, water, earth, air and aether. Plato also espoused this belief, although, his concept hypothesized that these elements held a specific geometrical and thus mathematical form. Aristotle believed that each fundamental element has its natural place; earth being the centre of the universe, then water, air and fire. When they are dislocated, Aristotle believed, that they have a natural motion, which requires no exterior cause; so bodies sink in water, air bubbles up, rain falls, flame rises in air and the aether element has an eternal, circular movement.
The elucidation of the contrasts in Aristotelian and Platonic thought has provided the stimulus for this inquiry. Although these two great thinkers disagreed on the theoretical basis of reality, the importance of their hypotheses can not be ignored, as their individual academic pursuits have provided invaluable theoretical insight into their respective scientific modes.