How does Descartes argue for ‘the cogito’?
- We know a number of claims by rational intuition, and we can use these as the premises in deductive arguments to gain knowledge of further claims. He argues that using these 2 methods we can gain knowledge of our own existence as mental substances (his cogito).
- Descartes is seeking to find out what he can know to be true. To achieve this he has decided to avoid believing in anything that isn’t ‘completely certain and indubitable’. The demon could manipulate our senses/memory/ and body as they are all a posteriori so we can’t trust these.
- Can’t doubt that he exists as this proves he exists- as something that thinks. He cannot be deceived that he thinks.
Outline and explain clear and distinct ideas.
- Clear: an idea is clear if it is present and accessible to the attentive mind.
- Distinct: It is so sharply separated from all other ideas that every part of it is clear.
- He connects these clear and distinct ideas to ‘the natural light’. ‘things that are revealed by the natural light are not open to any doubt, because no other faculty that might show them to be false could be as trustworthy as the natural light.
- So for Descartes, rational intuition is the ‘natural light’, our ability to know that clear and distinct ideas are true.
How might an empiricist respond to the cogito? (Continuity)
- Perhaps the demon is putting these thoughts into Descartes head?
- Descartes claims to be the same thing from one thought to another. However, Hume counters this and says: we don’t experience a continuing mental substance over time, we only experience a continually changing array of thoughts and feelings.
- In coming up with the idea of ‘a thinking thing’- a mental substance- we confuse similarity with identity. We’ve confused our experience of the similarity of our thoughts and feelings from one moment to the next with the idea that there is one identical ‘thing’ persisting from one thought to another.
- Humes argues that even if we experience thinking as active in this way, how does our experience enable us to move to the claim that I am one and the same active substance, persisting through time and different thoughts.
What does Hume mean by relations of ideas?
- A contradiction both asserts and denies something. For example, a true analytic proposition can’t be denied without contradiction.
- In a deductive argument, if you assert the premises, but deny the conclusions, then you contradict yourself. E.g. ‘3x5=15 and 30/2=15 but 3x5 and 30/2 are not equal’.
- Hume is claiming that we gain knowledge of relations of ideas through merely understanding concepts and through deductive inference from such understanding. To deny any claims we know this way would be a contradiction.
- We can make connect the 2 criteria. What we know that is intuitively or demonstratively certain is also what can be discovered purely by thinking-relations of ideas. On the other hand, propositions about what exists- matters of fact- we cannot know by a priori reasoning. We know them through experience.
What does Hume mean by matters of fact?
-What we experience here and now, or can remember. We gain it by using observation and employing induction and reasoning about probability.
- All knowledge that goes beyond what is present is our senses or memory rests on casual inference.
- We take our experience to be an effect of whatever fact we infer. For example, if I go out in the morning and all the streets are wet when they were dry yesterday evening, I’ll infer that it rained last night. I do this because I think that rain causes the streets to become wet, and if the whole area is wet, rather than a small part, il believe the cause is rain (not just some liquid spilling over).
- It is only our experience that enables us to infer from the existence of some cause to its effect, or from some effect to its cause. E.g. when you encounter a magnet you’ve never experienced before, could you deduct what effect it will have on metal?
- It is only our experience of what causes what that enables us to make causal inferences in particular cases.
Outline what Descartes says a substance is, an attribute and a mode.
- Substance: is defined as something that can exist independently, such as the mind, god and physical objects.
- Attribute: Is a property of a substance- the attribute of mind is thought, while extension is an attribute of physical objects.
- Mode: Is a particular determination of a property. So ideas are modes of mind- specific ways of thinking. Being specific sizes or shapes are modes of physical objects.
- A substance has more reality than an attribute, because a property cannot exist without a substance, and so is dependent on it. There can be no thoughts without a thinker.
- Modes, Therefore, also have less reality than substances.
- Ideas are modes of the attribute ‘thought’, which is possessed by thinking substances.
How can we apply Descartes definitions of substance, attribute and mode to cause and effect?
-He simply takes it to be a clear and distinct idea that the cause of something must contain at least as much reality as its effect. From this, he derives the claim that something can’t come from nothing. But In fact, it is easier for us to understand that the other way around-something can’t come from nothing, and so whatever is part of the effect must’ve originated in the cause.
- Ideas as modes of thought, the ‘intrinsic reality’ of all ideas is the same, and less than the reality of my mind, which is a substance. But ideas also represent something, e.g. an object, a size, a tune, a mind, god. Some of these things are substances, others are modes.
- The degree of reality of the thing that the thought it about determines the ideas ‘representative reality’.
- Just as we need to be able to explain where the heat in something hot comes from, so we need to be able to explain the representative reality of an idea. Just as neat comes from something hot; so an idea with a certain representative reality must come from something with at least as much intrinsic reality.
- So Ideas of substances can only be caused by substances; ideas of modes can be caused by either modes or substances.
How can we apply this idea of cause and effect to God?
- As a concept, it is a mode of thought, and so it means my mind- a substance- just as my mind causes many other ideas.
- But the special features of what God is a concept of, namely something infinite and perfect, mean that it has a representative reality greater than the intrinsic reality of my mind.
- If I invented the concept, God would contain things (infinity and perfection) that are not in its cause, because I am finite and imperfect. But this is impossible- there must be as much reality in the cause as in the effect.
- So only god, being perfect and infinite, could create a concept of something perfect and infinite.
What is an empiricist response to Descartes analysis of god as being the only possible cause of the idea of god!
- Is the concept of God innate l?
- David Hume rejects the claim that the concept of God cannot be created by our minds. We can form this concept by starting from ideas of finitude:
- ‘The idea of God comes from extending beyond all limits the qualities of goodness and wisdom that we find in our minds’.
- In ‘extending beyond all limits’ the ideas of finite goodness and wisdom we have from experience, we create an abstract negation of what is finite.
-From this we can create ideas of what is not-finite (infinite) and not-imperfect (perfect).
What is Descartes straightforward formal argument that physical objects exists?
P1. I have a clear and distinct idea of what a physical object is.
P2. (God exists and is supremely powerful)
P3. The only reason for thinking that God cannot make something is that the concept of it is contradictory.
C1. Therefore, God can make physical objects.
C2. Therefor, (if God exists) it is possible that physical objects exist.
Outline and explain the trademark argument.
-The Idea of God as a unique being that is supremely powerful and supremely perfect. The concept of such a being is innate within us, like a ‘trademark’ imprinted in our minds.
Formal summary:
- I have the concept of God.
- Everything that exists has a cause.
- Therefore, my concept of God must have a cause.
- The cause of an effect must have at least as much reality as the effect.
- My concept of God contains perfection.
- Therefore the cause of my concept of God must contain perfection.
- No being which is not god contains perfection.
- Therefore; the cause of my idea of God is god.
- Therefore, God exists.
How does Descartes respond to Humes Objection that we can create the idea of God?
- The Idea If imperfection of lack of perfection depends upon an idea of perfection, we can’t recognise that we are imperfect unless we have an idea of perfection with which to compare ourselves.
- Descartes admits that he can’t completely ‘grasp’ the idea of god as an infinite being because he is finite he merely understands it. With this admission, his claim that the concept of God is both clear and distinct and involves a positive conception of God’s infinity and perfection is unpersuasive.
What is the debate of rationalism vs knowledge empiricism?
-Concerns the relationship between the two kinds of knowledge (a priori and a posteriori) with the two kinds of truth (analytic and synthetic).
- Rationalism says there are some synthetic truths that can be known a priori.
- Knowledge empiricism says all knowledge of synthetic truths is acquired a posteriori.
