Aquinas's First Way highlights.ppt

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1、Aquinass First Way highlights,Its impossible for something to put itself into motion. Therefore, anything in motion is put into motion by something else. There isnt an infinite regress of movers in motion. Therefore, there is a prime mover, something that moves without itself being in motion, God.,A

2、quinass First Way,No self-movers: If x puts y into motion, then theres some respect in which x is in actuality and y is in potentiality. Its impossible for something to be in actuality and in potentiality in the same respect. Therefore, its impossible for something to put itself into motion.,Aquinas

3、s First Way,No infinite regress If there were an infinite regress of movers, thered be no first mover. But if there were no first mover, thered be no subsequent movers. And there clearly are movers. Therefore, there isnt an infinite regress of movers.,Aquinass First Way full-dress version,Anything i

4、n motion is put into motion by something. Its impossible for something to put itself into motion. If x puts y into motion, then theres some respect in which x is in actuality and y is in potentiality. Its impossible for something to be in actuality and in potentiality in the same respect. Therefore,

5、 anything in motion is put into motion by something else. If everything in motion were put into motion by something else itself in motion, thered be an infinite regress (or a loop?) There isnt an infinite regress of movers in motion. If there were an infinite regress of movers, thered be no first mo

6、ver. But if there were no first mover, thered be no subsequent movers. And there clearly are movers. Therefore, there is a prime mover, something that moves without itself being in motion, God. I suspect Aquinas needs further argument to show that there is only one prime mover,Craigs kalam cosmologi

7、cal argument,Whatever begins to exist has a cause. The universe began to exist. Therefore, the universe has a cause. If the universe has a cause, it must be immaterial, timeless, and changeless uncaused personal Therefore, the universe has an uncaused, immaterial, timeless, changeless, and personal

8、cause.,The universe began to exist,Mathematical-philosophical: Actual infinites avoid contradiction in the mathematical realm only due to certain restrictions. But such restrictions have no place in the real world. Therefore, actual infinites could not avoid contradiction in the real world. If the u

9、niverse didnt begin to exist, then there would be an actually infinite number of past events. Therefore, the universe began to exist. Scientific: According to standard Big Bang cosmology, the universe began to exist.,Whatever begins to exist has a cause,Obviously true Something cannot come from noth

10、ing. “Things cannot just pop into being out of nothing.” Quantum mechanics? Only certain interpretations of quantum mechanics involve indeterminism, and even those do not involve anything coming into being from nothing. What about God? God doesnt begin to exist, so the principle doesnt apply to God.

11、 The universe, on the other hand, did begin to exist, so it must have a cause.,Getting to God,Immaterial, timeless, and changeless The cause of the universe is not located within space or time. Uncaused The cause of the universe cannot have a cause, because “weve seen that there cannot be an infinit

12、e regress of causes” Personal The cause must somehow be timeless and yet have a effect in time. But if the timeless cause were impersonal and “mechanical”, then it would have a timeless effecti.e., then the universe would be eternal. So the timeless cause must be a person who freely chooses to bring

13、 about a effect in time.,Infinity,Can actual infinites exist in the real world? If numbers are real, then, since there are infinitely many numbers, it follows that actual infinities do exist in the real world (hence Craig rejects Platonist realism about numbers). If space consists of infinitely many

14、 segments, then actual infinities do exist in the real world. N.B.: Its not enough for space to be infinitely divisible. Craig will say that this is a merely potential infinite, not an actual infinite. Isnt God infinite? Craigs arguments are against the real existence of an actually infinite number

15、of things. Presumably God is infinite in some other sense of the term.,Causation,Begins to exist x exists at some time, and there is some time immediately beforehand where x doesnt exist This doesnt apply to the universe Can something begin to exist without a cause in this sense? x exists at some ti

16、me, and there is no time beforehand This does apply to the universe Can something begin to exist without a cause in this sense? Perhaps the premise whatever begins to exist has a cause is less plausible in the second sense (the one that applies to the universe).,Causation,Simultaneous causation On s

17、tandard Big Bang cosmology, lets suppose, there is no time before the universe. But if a cause must precede its effect in time, then the universe has no cause. So Craig rejects the claim that a cause must precede its effect: he allows for simultaneous causation (ball-cushion example). Creation ex ni

18、hilo Craig holds that God created the universe ex nihiloout of nothing. But if it seems obviously true that nothing can begin to exist without a cause, doesnt it also seem obviously true that nothing can be created ex nihilo?,Part IX,Demeas argument Its a cosmological argument He calls it “the argum

19、ent a priori” Its supposed to get you all the way to a theistic God: i.e., only one God, who is infinite A priori vs. a posteriori The term a priori is often used to mean independent of experience/observationmath is supposed to be a priori And a posteriori is used to mean based on experience/observa

20、tionthe natural sciences are supposed to be a posteriori,Demeas argument,Principle of sufficient reason (PSR) “Whatever exists must have a cause or reason of its existence” Two options Either “tracing an infinite succession, without any ultimate cause at all” or “at last having recourse to some ulti

21、mate cause, that is necessarily existent” The first option is absurd For “the whole eternal chain or succession. requires a cause or reason, as much as any particular object which begins to exist in time” “The question is still reasonable, why this particular succession of causes existed from eterni

22、ty, and not any other succession, or no succession at all.” So were forced to accept the second option,Cleanthes objections,No a priori proofs of existence claims When you demonstrate something a priori, you show why the opposite is inconceivable and contradictory. Like in math But with existence cl

23、aims, both sides are conceivable, neither one is contradictory. Whatever we can conceive of as existing, we can also conceive of as not existing So its impossible to give an a priori demon-stration of a things existence.,Cleanthes objections,“Necessary existence” If somethings existence is necessary

24、, then its nonexistence should be inconceivable. But you can always at least conceive of a things nonexistence. So there cant be any such thing a necessarily existing being.,Cleanthes objections,Necessary being: God or Universe? Even if there is a necessarily existing being, why think its a theistic

25、 God? Why not just say its the physical universe? Admittedly, its hard to see how the physical universe could be a necessarily existing beingafter all, we can always conceive of the nonexistence of any lump of matter. But (as just mentioned), its equally hard to see how God could be a necessarily ex

26、isting beingafter all, its equally true that we can always conceive of Gods nonexistence.,Cleanthes objections,Causation and priority in time If theres an infinite chain of contingent beings, then there isnt any time before all the contingent beings. But a cause has to be before its effect. So there

27、 cant be a cause of an infinite chain of contingent beings.,Cleanthes objections,No need for extra explanation If theres an infinite chain of contingent beings, then theres a satisfactory explanation for each individual contingent being. But if each individual is explained, then the entire collectio

28、n of individuals is also explained. After all, its not like the collection is some brand-new thing, over and above all the individuals. So there is nothing left unexplained.,Philos objection,Perhaps everythings necessary It might well be true that everything in the physical universe, even though it

29、seems contingent, is actually necessary. If so, it would be impossible for things to be different than they are. And so thered be no need to explain why things are this way instead of that way, or why theres something instead of nothing.,Philos closing observation,This argument only convinces metaph

30、ysicians People who are into abstract reasoning about deep topics (especially people who do mathematics) are the only ones who put any stock in such arguments. Everyone else cant shake the feeling that the arguments have some problem somewhere, even if they cant put their finger on whats wrong with

31、them.,Modal cosmological arguments (Review),The target Whats the target? The view that says theres nothing but contingent beings. The goal is to disprove this view. If successful, it follows that there is a necessary being. The problem If theres nothing but contingent beings, then were left with an

32、unexplained fact. Theres no explanation for why this collection of contingent beings exists rather than some different collection or nothing at all. So the problem is that this view leaves us with a brute factan unexplained collection of contingent beings. I should add that Aquinas seems to have a d

33、ifferent problem with the nothing but contingent beings view.,Modal cosmological arguments (Review),Nothing but contingent beings There could be nothing but a finite chain of dependence. There could also be nothing but an infinite chain of dependence. There could also (perhaps!) be nothing but a loo

34、p of dependence. The PSR But on any of these options, something is left unexplained. In particular, on any of these options, the question “Why does this chain/loop exist?” has no answer. This violates the Principle of Sufficient Reason, which says that there is an explanation (a reason/cause) for ev

35、erything (everything that exists, or every positive fact, .),Humes most famous objection (Review),An infinite chain would satisfy the PSR Cleanthes says that, with an infinite chain of dependence, nothing is left unexplained. After all, each individual is explained by the previous individual. And th

36、e collection of individuals isnt anything over and above all the individuals. So, since each individual is explained, then the entire collection is explained. So the PSR is satisfiedeverything has an explanation.,Possible replies to Hume,Loop reply In a loop of dependence, each individual is explain

37、ed by the previous individual. But it looks like this leaves the entire loop unexplained. So this shows that, even if every individual in a collection is explained, the entire collection might still be unexplained. Perhaps Hume can get out of this problem by insisting that there couldnt be a loop of

38、 dependence in the first place Circularity reply Hume says theres an explanation for the entire collection. But what is this explanation? What gets cited in this explanation? The only beings that exist are the ones in the infinite chain, so those are the only beings that could be cited in an explanation. So any explanation of the entire collection would have to cite beings belonging to the collection. So any explanation would be circular.,