Parmenides was deeply influenced by Xenophanes (Parmenides may have been his student). Recall that Xenophanes criticized the pre-philosophical tradition of relying on the gods to explain natural phenomena. Xenophanes maintained that there was a strict division between mortal and divine knowledge that cannot be crossed. Parmenides upheld this distinction, but went even further by claiming that the opinions of mortals are universally unreliable.
If mortals do not have access to divinity, but cannot attain knowledge without divine aid, how can they move beyond their flawed opinions and discover the nature of reality? Parmenides' answer is that there are signs we can follow, which point to genuine reality: signs that "turn to metaphysics."
Recall that metaphysics seeks to uncover and describe the ultimate nature of reality. In this context, it is a quest to look beyond the mortal world, the world of the senses and of unreliable opinion, to perceive reality as it truly is. Metaphysics is the answer to how humans can take a god’s-eye view and discover what is real.
Substance monism is a component of Parmenides’ metaphysics, that has been attributed to him by later sources. It is the view that all of reality is one object, usually translated as the “what-is.” The "what-is" is a term for the way things are: The True. Parmenides also posited a corresponding “what-is-not.” This can be thought of as The False. Together, these two concepts create a duality in Parmenidean metaphysics.
In this metaphysical system, what-is, is, but what-is-not, cannot be. That this must be so becomes evident when basic questions are asked: where would what-is-not come from? How would it come into being?
What-is-not cannot come from what-is. The False cannot come from The True. Non-being cannot come from being. However, it is also impossible for what-is-not to come from nothing, since nothing cannot produce anything. As a result, the universe cannot change from what-is to what-is-not. If "The True" is true, it cannot become "The False." At the same time, what-is cannot cease to be, since transformation from being to non-being is metaphysically impossible, according to Parmenides.
In this system, what-is is eternal and unchanging, because change would require the universe to pass from what-is to what-is-not. Although this is the conclusion to which Parmenides’ metaphysical analysis leads, it is not the universe with which we are familiar. Our universe is changing and impermanent. This creates a duality between the genuine, unchanging realm of reality, and the changing world of appearance. Parmenides’ way focuses on the former, but the way of opinion, in which observers do not realize that this transient world of change is illusory, is focused on the latter.
Maintaining that change is illusory, as Parmenides does, seems to run counter to common sense. You may be tempted to dismiss Parmenides’ view for that reason alone, but you would be wise to avoid a quick dismissal of his conclusions. Think about all of the things we know are true, despite what "common sense" tells us.
EXAMPLERight now, you are moving at 67,000 miles per hour while standing on a round surface that is rotating at up to 1,000 miles per hour. Space itself is expanding, and it curves around heavy objects.
These examples show that “strange” cannot be equated with “false.” This is especially true when you are forced to choose between two peculiar options. For example, when you think about the origin of the universe, it seems as if you must choose between a Big Bang, in which all matter in the universe comes randomly into being, and a creator god who waited for an infinity before deciding to create the cosmos 13 billion years ago. In this debate, one side calling the other’s view “strange” is a case of the pot calling the kettle black. Such accusations are not significant challenges to any view. When considering big questions, things sometimes get weird.
One of Parmenides’ most famous students, Zeno of Elea, wrote a short book describing paradoxes. He demonstrated that motion was a far stranger phenomenon than the "commonsense" view of it held by most people would allow. By doing so, Zeno showed that rejection of Parmenides’ explanations of how things work simply because they're "strange," and because they refuted "commonsense" opinions based on what seemed to be obvious and apparent, was illegitimate criticism.
There are many kinds of paradoxes, as a result of how slippery the notion of “absurdity” is (e.g., is the presence of absence an absurdity?). “Paradox” covers a large number of logical and metaphysical oddities. Socrates and Plato, who we'll discuss later in this course, emphasized precise definition of important words including “justice,” “craft,” and “piety.” They believed that precise definitions were required in order to be clear about the concepts being discussed. However, it can be difficult to define terms like these with precision. In contrast, the oddities uncovered by Zeno are relatively straightforward.
Zeno explained a number of paradoxes, but only a few of them have been preserved. His paradoxes of motion fall into two categories: those which demonstrate the difficulties involved in positing time as a continuum, and those which demonstrate the difficulties involved in positing time as being composed of discrete moments.
To argue against a continuum, Zeno raises considerations which include the following:
If time is a continuum, how could we ever get from one place to another? To move from A to B, we must first halve the distance, then halve it again, then halve it again, and so on. That is, we must complete an infinite task through a series of finite actions.
To argue against a discrete notion of time, imagine an arrow being fired. Consider one point in time (i.e., one moment), and label it T1. At time T1, the arrow will have a specific position, P1. At the next moment, T2, the arrow has moved to a new position, P2. When did the motion occur? Between moments? There is no such thing as "between moments," if time is discrete. If we assume that time is composed of discrete moments, the arrow didn’t move, even though it is no longer at P1, but is now at P2. This is also absurd.
Source: Archer by damar bintang from the Noun Project (CC), bullseye by Dinosoft Labs from the Noun Project (CC), Arrow by Valeriy from the Noun Project (CC). All retrieved from The Noun Project :www.thenounproject.com