Elementary Logic - Notes for the course PDF

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Elementary Logic

Session 1 Introductory lesson and class discussion! Course Description 1. Who am I?! 2. What can we know?! 3. Does god exist?! 4. How should I behave! 5. What is beauty?! 6. How should we organise society?" Philosophy as a Method:! Use this to come up with conclusions that are hard to refute. • Rational Arguments! • Logic! Philosophy as a Subject Matter: • They are deep and lasting interest to human beings! • They have answers, but the answers have not yet been settled on! • The answers cannot be decided by science, faith or common sense"

Session 2 Reading: Rene Descartes, “Meditations”

Topic I: Who am I? The Philosophy of Mind.

Meditations First meditation He has resolved to sweep away all he thinks he knows and to start again from the foundations. Everything that the Meditator has accepted as most true he has come to learn from or through his senses. However, the Meditator realizes that he is often convinced when he is dreaming that he is sensing real objects. He feels certain that he is awake and sitting by the fire, but reflects that often he has dreamed this very sort of thing and been wholly convinced by it.! While we can doubt studies based on composite things, like medicine, astronomy, or ! physics, he concludes that we cannot doubt studies based on simple things, like arithmetic and geometry.! Page 1 of 35

On further reflection, the Meditator realizes that even simple things can be doubted. Omnipotent God could make even our conception of mathematics false. If we suppose there is no God, then there is even greater likelihood of being deceived, since our imperfect senses would not have been created by a perfect being.! He supposes that not God, but some evil demon has committed itself to deceiving him so that everything he thinks he knows is false. By doubting everything, he can at least be sure not to be misled into falsehood by this demon.! Analysis: - Foundation of modern skepticism! - Metaphysical underpinning of Descartes´s new physics! - Descartes' doubt is a methodological and rational doubt! Second meditation The Meditator is firm in his resolve to continue his search for certainty and to discard as false anything that is open to the slightest doubt. Recalling the previous meditation, he supposes that what he sees does not exist, that his memory is faulty, that he has no senses and no body, that extension, movement and place are mistaken notions. He has conceded that he has no senses and no body, but does that mean he cannot exist either? He has also noted that the physical world does not exist, which might also seem to imply his nonexistence. And yet to have these doubts, he must exist. For an evil demon to mislead him in all these insidious ways, he must exist in order to be misled. Here comes the cogito argument: "I must finally conclude that this proposition, I am, I exist, is necessarily true whenever it is put forward by me or conceived in my mind." The Meditator's next question, then, is what this "I" that exists is. He doubts on the existence of the body, the soul, but he cannot doubt that he thinks. The Meditator concludes that, in the strict sense, he is only a thing that thinks.! The Meditator tries to clarify precisely what this "I" is, this "thing that thinks." He concludes that he is not only something that thinks, understands, and wills, but is also something that imagines and senses. His sensory perceptions may not be veridical, but they are certainly a part of the same mind that thinks.! The senses, as we have seen, cannot be trusted. Similarly, he concludes, he cannot trust the imagination. ! The Meditator concludes that, contrary to his initial impulses, the mind is a far better knower than the body. Further, he suggests, he must know his mind far better than other things. After all, as he has admitted, he may not be perceiving the piece of wax at all: it may be a dream or an illusion. But when he is perceiving the piece of wax, he cannot doubt that he is perceiving nor that he is judging what he perceives to be a piece of wax, and both of these acts of thought imply that he exists. ! The Meditator concludes that he can know at least that he exists, that he is a thinking thing, that his mind is better known than his body, and that all clear and distinct perceptions come by means of the intellect alone, and not the senses or the imagination. Analysis: ! - The cogito argument is so called because of its Latin formulation in the Discourse on Method: "cogito ergo sum" ("I think, therefore I am"). This is possibly the most famous single line in all of philosophy, and is generally considered the starting point for modern Western philosophy. !

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- In the Cartesian conception of mind, there is a sharp distinction between mind and world, where all those activities--like sensing and imagining--that could take place in dreams or in disembodied minds are considered mental activities, and exist only in the mind.! Class comments: He is attempting to form a stronger foundation of thinking from the get go, by eliminating all logic that isn’t necessarily a guarantee, despite it being well believed. By doing this, he is attempting to guarantee that all his philosophy that comes after that is not built starting on a weak link.! The cogito is essentially Descartes trying to find a basis for his thoughts and essentially breaks it down to an immovable certainty, which is essentially the only thing he can prove is that he is present in his mind; the rest being subject to his minds own distortions - which is where it gets to 'I think therefore I am'! He doesn’t believe that the bodies are strictly perceived by the imagination but rather by the intellect alone and that these concepts need to be understood rather than being sensed by senses as we can’t trust them because he doesn’t have the certainty they exist. The absolute certainty for him is his mind and that he is something, because he thinks so he is.!

René Descartes’ Philosophy How do our minds know? Descartes had no doubt that human beings know some things and are capable of discovering others, including fundamental truths about the basic structure of reality. Yet he believed that Aristotelian philosophy contained a basic error about the manner in which truths are to be gained. In the Aristotelian scheme all knowledge arises from the senses. Descartes held that the human intellect is able to perceive the nature of reality through a purely intellectual perception.! In the#Meditations, he held that the essence of matter could be understood by innate ideas, independently of any sensory image. To that extent, his later position agrees with the Platonic tradition in philosophy. which denigrated sensory knowledge and held that the things known by the intellect have a higher reality than the objects of the senses. Descartes, however, was no Platonist. In Descartes' scheme of mental capacities, knowledge does not arise from the intellect alone. The intellect may present some content as true, but by itself it does not affirm or deny that truth. That function belongs to the will.! Metaphysical first principles as known by the intellect acting alone should attain absolute certainty. Practical knowledge concerning immediate benefits and harms is known by the senses. Objects of natural science are known by a combination of pure intellect and sensory observation: the pure intellect tells us what properties bodies can have, and we use the senses to determine which particular instances of those properties bodies do have.!

The mark of truth At the beginning of the Third Meditation, Descartes declares “I now seem to be able to lay it down as a general rule that whatever I perceive very clearly and distinctly is true” (7:35). Clarity and distinctness of intellectual perception is the mark of truth. But what is the method for recognising clarity and distinctness?! We have a clear and distinct perception of something if, when we consider it, we cannot doubt it.! Descartes held that any act of judgment, such as the affirmation “I think, therefore I am,” involves both the intellect and will. The intellect perceives or represents the content of the judgment; the will affirms or denies that content. ! Page 3 of 35

The nature of reality The main metaphysical results that describe the nature of reality assert the existence of three substances, each characterized by an essence. The first and primary substance is God, whose essence is perfection. In fact, God is the only true substance, that is, the only being that is capable of existing on its own. The other two substances, mind and matter, are created by God and can only exist through his ongoing act of preservation or conservation, called God's “concurrence”.! Descartes' arguments to establish the essences of these substances appeal directly to his clear and distinct perception of those essences. The essence of matter is extension in length, breadth, and depth. The essence of mind is thought. Besides existence and duration, minds have the two chief powers or faculties previously mentioned: intellect and will. The intellectual (or perceiving) power is further divided into the modes of pure intellect, imagination, and sense perception. The will is also divided into various modes, including desire, aversion, assertion, denial, and doubt. These always require some intellectual content (whether pure, imagined, or sensory) upon which to operate. !

Mind–body relation In the Second Meditation, he established that he could not doubt the existence of himself as a thinking thing, but that he could doubt the existence of matter. However, he explicitly refused to use this situation to conclude that his mind was distinct from body, on the grounds that he was still ignorant of his nature. Then, in the Sixth Meditation, having established, to his satisfaction, the mark of truth, he used that mark to frame a positive argument to the effect that the essence of mind is thought and that a thinking thing is unextended; and that the essence of matter is extension and that extended things cannot think.! This conclusion in the Sixth Meditation asserts the well-known substance dualism of Descartes. That dualism leads to problems. As Princess Elisabeth, among others, asked: if mind is unextended and matter is extended, how do they interact?!

Session 3: Non-class learning Reading: David Hume, “On personal identity” Movie: Richard Linklater, “Waking Life”!

Commentary on Walking Life (Germain’s) Around the 9:20 mark of the film, the speech given by the professor immediately caught my attention. The character discusses Existentialism, a philosophical approach that values the existence of an individual as an autonomously responsible agent with direct control of their path and pursuit through free will; Whilst existence is particular to each individual, there is a Descartian element to life that says “Your definition of being is your own, but it is”. Existentialists define and value themselves by their very Being.## The professor uses this thinking to suggest it is lacking in our current culture and maybe the reason for a loss in virtue of young people; replaced by victim culture where we are constantly looking for others to blame, fueled by postmodernist ideology. He makes points that I have long believed. Characterizing people as social constructions who are influenced by marginalisation creates a culture of self-defeatism. Whilst some points of the postmodernists are irrefutable, I have yet understood how acting out the entirety of the postmodernist belief would possibly create a more fruitful world (though they may argue with me that my opinion of what constitutes fruitful is Page 4 of 35

a social construction; which I would agree with partially but not entirely as of now). Whilst existentialism may, as the professor suggests, be seen as a philosophy of despair, with the right approach and determination to better yourself, it can blossom into a strive to be virtuous solely for reasons you yourself have deemed important. This existentialist idea then bled over into my reading of David Hume. Hume talks about identity as an ever-changing state. He uses the idea of a Republic. Whilst under the same name, a Republic could change its governors, laws and even constitutions but its identity is held by a thread through causation, that we interpret as a soul. Though to Hume, our identity undergoes clear change and refrains from being a constant singularity. Hume does relate these changes to be in our own control, though. Through this, we can find some essence of existentialism, such as in the film, flowing into Humes thinking; ultimately, we are because we think we are, no matter how that identity may change over time through the course of our own will.# Whilst Hume is not an existentialist per se, the connection between these two pieces caught my attention, revealing certain parallels. I think both the professor in the film and Hume may agree that virtue is derived and sought out personally, whether this is in a constant or ever-changing identity.!

Ship of Theseus It is supposed that the famous ship sailed by the hero#Theseus#in a great battle was kept in a harbour as a museum piece, and as the years went by some of the wooden parts began to rot and were replaced by new ones; then, after a century or so, every part had been replaced. The question then is if the "restored" ship is still the same object as the original.! If it is, then suppose the removed pieces were stored in a warehouse, and after the century, technology was developed that cured their rot and enabled them to be reassembled into a ship? Is this "reconstructed" ship the original ship? If it is, then what about the restored ship in the harbour still being the original ship as well?!

An overview of Hume’s theory of Personal Identity! Before we look at Hume’s theory of personal identity, let us first turn to Hume’s theory of identity Hume starts off by investigating where we get this notion of identity from. Hume argues that looking at#one!object can never give us the idea of identity but only that of unity. For there to by identity we would need something to reference our object to. Seeing an object gives us the idea of unity, seeing the same object again, at another time, gives us the idea of numbers. The idea of identity allows us to link the idea of unity with that of numbers, and tells us that we are viewing the#same#object. This means that the idea of identity is not one we form based on the senses, but one we construct in the mind.! It is especially the notion of a persistent self which makes Hume question our idea of personal identity. We change all the time, yet we are said to remain the same, how can this be? It must be because of a self which is constant, but despite great effort, Hume cannot seem to find such a thing. Every time we look into ourselves in order to find an unchanging continuous self, we are presented with different fleeting perceptions ! What there is, Hume concludes, is not a self, but a bundle of perceptions, ever fleeting, popping up and being replaced by other perceptions. According to Hume, a perception exists when it is present to the senses. This means that when we remember something we have viewed in the past, we are pulling perceptions back into our attention. Yet if these perceptions resemble the perception of something now being viewed, we are prone to think them the same perception, when in fact they are not. It is this reasoning that leads Hume to the conclusion that identity cannot be derived from reason but must be derived from the imagination. ! Hume thus claim that the identity we prescribe ourselves cannot be a perfect one because we are never the same perception, unchanging and uninterrupted, but quite the opposite. It is therefore impossible to have sameness over time, numerical or otherwise.! Page 5 of 35

Hume digs deeper and uncovers that this illusion of identity is brought about by two different concepts namely resemblance and causation. Starting with resemblance Hume argues that when we perceive ourselves or another, we form a perception of what we see, this perception can, and often does, resemble one we have had before. Remembering this past perception and its resemblance to the present one, creates an easy transition of perceptions between the two perceptions, tricking us into thinking we are seeing a continued existence.! On causation Hume writes that if certain perceptions follow each other enough times, we come to assume that they are linked, and that one produces the other. Yet each perception is, according to Hume, a separate and isolated existence. Because the gap between cause and effect is so minute between our perceptions, we fail to see them as multiple perception and mistakenly assume that they are in fact one continuous perception, but this is only a trick of the mind.! It is important to note that Hume is not saying that there are no “selves” or “persons”, what he is saying is, that we can never perceive"sameness"of self or person, over time. As we have already seen, Hume argues that the whole concept of identity over time is an illusion, yet to make matters worse, we seem to also confuse numerical (perfect identity) and qualitative identity. We mistake multiple sounds for one sound because the sounds resemble each other. This is the same as we have seen above regarding our perception of self. We need only look at the example of the river Hume employs, to realize just how selective our perceptions really are. Claiming that a river remains the#same!over a course of time, would for Hume be mistaking numerical identity (perfect identity) with qualitative identity, since all the parts are gradually changed over time, and thus we cannot have an uninterrupted and unchanging perception of it.!

David Hume’s Philosophy Empiricism Every modern philosopher accepted some version of the#theory of ideas—the view that we immediately perceive certain mental entities called#ideas, but don’t have direct access to physical objects. Hume holds an#empiricist#version of the theory, because he thinks that everything we believe is ultimately traceable to experience.! He begins with an account of#perceptions, because he believes that any intelligible philosophical question must be asked and answered in those terms. He uses#perception#to designate any mental content whatsoever, and divides perceptions into two categories,#impressions"and"ideas.! Impressions#include#sensations#as well as#desires,#passions, and#emotions.#Ideas#are “the faint images of these in thinking and reasoning”. He thinks everyone will recognize his distinction, since everyone is aware of the difference between#feeling#and#thinking.!

The Copy Principle In the#Treatise, Hume qualifies his claim that our ideas are copies of our impressions, making clear that it applies only to the relation between#simple ideas"and"simple impressions. He offers this “general proposition”, usually called the#Copy Principle, as his “first principle … in the science of human nature”: All our simple ideas in their first appearance are derived from simple impressions, which are correspondent to them, and which they exactly represent. ! He argues first that there is a one–to–one correspondence between simple ideas and simple impressions. He can’t#prove#that this correspondence holds universally, since he can’t examine every individual impression and idea. But he is so confident the correspondence holds that he challenges anyone who doubts it to produce an example of a simple impression without a corresponding simple idea, or a simple idea without a corresponding simple impression. Since he is certain they will fail, he concludes that there is a#constant conjunction#between simple impressions and simple ideas.! Page 6 of 35

Next, he maintains that this constant conjunction is so universal that the correspondence can’t be a matter of chance. There must be a causal connection between them, but do ideas cause impressions or do impressions cause ideas?! Finally, he argues that experience tells us that simple impressions always precede and thus cause their corresponding ideas. To support this claim, he appeals to two sorts of cases. First...