leibniz

lesbian on 3rd way

argument based off of a’s 3rd way

• improves on Aquinas’ 3rd way by removing unnecessary reasoning about nothing once existence 

• Bases his argument on the principle of sufficient reason, which does both the job of a causal principle and an argument against infinte regress 

• Shows that there must be not just any causal explanation, but a causal explanation which provides an ultimately sufficient reason for everything that exists 

• Strengthens the argument by making it dependent on only one claim 

• A priori 

principle of sufficient reason + against brute facts

• Argues that it is simply irrational not to look for an explanation of things 

• We can always know the sufficient explanation of something 

• We may not have the evidence/ the intelligence to work out the sufficient explanation, but there always IS a sufficient explanation (whether we can solve it or not), and as rational creatures we are entitled to seek it 

distinction between proximate and sufficient reasons

• A proximate reason is an incomplete explanation: it involves the immediate cause, the thing that is immediately responsible 

• A sufficient reason is a complete or ultimate explanation 

leibniz proof

• p1= for every true fact or assertion, there is a sufficient reason why it is thus and not otherwise 

• p2= there are two types of truth: truths of reasoning and truths of fact 

• p3a= truths of reasoning are necessary, so their opposite is impossible, the sufficient reason for truths of reasoning can be discovered a priori 

• p3b= truths of fact are contingent, so their opposite is possible. the sufficient reason for truths of fact cannot be discovered through other contingent truths, because they too require a sufficient explanation, and so on 

• c1= a sufficient reason for contingent facts must be found outside a series of contingent things 

• c2= the sufficient reason for contingent facts must be a necessary substance 

• c3= that necessary substance is god → god must exist 

geometry eg

• Leibniz (who was a brilliant mathematician) uses the example of a geometry text book.

• You might ask, "Where did this geometry book come from?" and an answer might be, It was copied from a previous geometry text book.

• Leibniz imagines an "eternal" geometry book - a set of geometry text books stretching into the past forever, each one copied from the one before.

• If you ask, "Where did this geometry book come from?" you would not be satisfied with a proximate answer (it was copied from the previous book) - you want a sufficient reason, you want to know why ALL the books exist, why there is such a thing as geometry text books at all. 

WEAKNESS: hume

• Hume argued that we could not logically move from the idea that everything in the universe has a reason, to say that the universe as a whole must have a reason. 

• we can imagine something coming into existence without a cause: it is not an incoherent idea 

• In An Enquiry Concerning Human Understanding (1748), Hume argues that our belief in causation does not arise from reason or logic but from habitual association: 

• When we observe constant conjunctions — for example, fire always preceding heat — we come to expect the second event whenever we encounter the first. 

• However, no amount of experience can logically guarantee the connection between cause and effect. There is no contradiction in imagining the effect not following the cause. 

COUNTER to hume

• but others have objected that just because you could imagine something existing without a cause, it does not follow that in reality it could exist without a cause 

• anscombe gave the e.g that we can imagine a rabbit which has no parents and just existed, but obviously this would not be an actual possibility just bc we imagined it 

WEAKNESS: russell

• Russel made a similar point in the 20th century by saying that just bc every human being has a mother, this doesn’t mean that the human species as a whole has a mother 

• it is overstepping the rules of logic to move from individual causes of individual things, to the view that the totality has a cause