30 ideas
| 4642 | No fact can be real and no proposition true unless there is a Sufficient Reason (even if we can't know it) [Leibniz] |
| Full Idea: The principle of sufficient reason says no fact can be real or existing and no proposition can be true unless there is a sufficient reason why it should be thus and not otherwise, even though in most cases these reasons cannot be known to us. | |
| From: Gottfried Leibniz (Monadology [1716], §32) | |
| A reaction: I think of this as my earliest philosophical perception, a childish rebellion against being told that there was 'no reason' for something. My intuition tells me that it is correct, and the foundation of ontology and truth. Don't ask me to justify it! |
| 2115 | Everything in the universe is interconnected, so potentially a mind could know everything [Leibniz] |
| Full Idea: Every body is sensitive to everything in the universe, so that one who saw everything could read in each body what is happening everywhere, and even what has happened and will happen. | |
| From: Gottfried Leibniz (Monadology [1716], §61) |
| 2111 | Falsehood involves a contradiction, and truth is contradictory of falsehood [Leibniz] |
| Full Idea: We judge to be false that which involves a contradiction, and true that which is opposed or contradictory to the false. | |
| From: Gottfried Leibniz (Monadology [1716], §31) |
| 7644 | The monad idea incomprehensibly spiritualises matter, instead of materialising soul [La Mettrie on Leibniz] |
| Full Idea: The Leibnizians with their monads have constructed an incomprehensible hypothesis. They have spiritualized matter rather than materialising the soul. | |
| From: comment on Gottfried Leibniz (Monadology [1716]) by Julien Offray de La Mettrie - Machine Man p.3 | |
| A reaction: I agree with La Mettrie. This disagreement shows, I think, how important the problem of interaction between mind and body was in the century after Descartes. Drastic action seemed needed to bridge the gap, one way or the other. |
| 11857 | He replaced Aristotelian continuants with monads [Leibniz, by Wiggins] |
| Full Idea: In the end Leibniz dethroned Aristotelian continuants, seen as imperfect from his point of view, in favour of monads. | |
| From: report of Gottfried Leibniz (Monadology [1716]) by David Wiggins - Sameness and Substance Renewed 3.1 | |
| A reaction: I take the 'continuants' to be either the 'ultimate subject of predication' (in 'Categories'), or 'essences' (in 'Metaphysics'). Since monads seem to be mental (presumably to explain the powers of things), this strikes me as a bit mad. |
| 7843 | Is a drop of urine really an infinity of thinking monads? [Voltaire on Leibniz] |
| Full Idea: Can you really maintain that a drop of urine is an infinity of monads, and that each one of these has ideas, however obscure, of the entire universe? | |
| From: comment on Gottfried Leibniz (Monadology [1716]) by Francois-Marie Voltaire - works Vol 22:434 | |
| A reaction: Monads are a bit like Christian theology - if you meet them cold they seem totally ridiculous, but if you meet them after ten years of careful preliminary study they make (apparently) complete sense. Defenders of panpsychism presumably like them. |
| 12751 | It is unclear in 'Monadology' how extended bodies relate to mind-like monads. [Garber on Leibniz] |
| Full Idea: It is never clear in the 'Monadologie' how exactly the world of extended bodies is related to the world of simple substances, the world of non-extended and mind-like monads. | |
| From: comment on Gottfried Leibniz (Monadology [1716]) by Daniel Garber - Leibniz:Body,Substance,Monad 9 | |
| A reaction: Leibniz was always going to hit the interaction problem, as soon as he started giving an increasingly spiritual account of what a substance, and hence marginalising the 'force' which had held centre-stage earlier on. Presumably they are 'parallel'. |
| 19363 | Changes in a monad come from an internal principle, and the diversity within its substance [Leibniz] |
| Full Idea: A monad's natural changes come from an internal principle, ...but there must be diversity in that which changes, which produces the specification and variety of substances. | |
| From: Gottfried Leibniz (Monadology [1716], §11-12) | |
| A reaction: You don't have to like monads to like this generalisation (and Perkins says Leibniz had a genius for generalisations). Metaphysics must give an account of change. Succeeding time-slices etc explain nothing. Principle and substance must meet. |
| 19352 | A 'monad' has basic perception and appetite; a 'soul' has distinct perception and memory [Leibniz] |
| Full Idea: The general name 'monad' or 'entelechy' may suffice for those substances which have nothing but perception and appetition; the name 'souls' may be reserved for those having perception that is more distinct and accompanied by memory. | |
| From: Gottfried Leibniz (Monadology [1716], §19) | |
| A reaction: It is basic to the study of Leibniz that you don't think monads are full-blown consciousnesses. He isn't really a panpsychist, because the level of mental activity is so minimal. There seem to be degrees of monadhood. |
| 7931 | If a substance is just a thing that has properties, it seems to be a characterless non-entity [Leibniz, by Macdonald,C] |
| Full Idea: For Leibniz, to distinguish between a substance and its properties in order to provide a thing or entity in which properties can inhere leads necessarily to the absurd conclusion that the substance itself must be a truly characterless non-entity. | |
| From: report of Gottfried Leibniz (Monadology [1716]) by Cynthia Macdonald - Varieties of Things Ch.3 | |
| A reaction: This is obviously one of the basic thoughts in any discussion of substances. It is why physicists ignore them, and Leibniz opted for a 'bundle' theory. But the alternative seems daft too - free-floating properties, hooked onto one another. |
| 17554 | There must be some internal difference between any two beings in nature [Leibniz] |
| Full Idea: There are never two beings in nature that are perfectly alike, two beings in which it is not possible to discover an internal difference, that is, one founded on an intrinsic denomination. | |
| From: Gottfried Leibniz (Monadology [1716], §09) | |
| A reaction: From this it follows that if two things really are indiscernible, then we must say that they are one thing. He says monads all differ from one another. People certainly do. Leibniz must say this of electrons. How can he know this? |
| 2112 | Truths of reason are known by analysis, and are necessary; facts are contingent, and their opposites possible [Leibniz] |
| Full Idea: There are two kinds of truths: of reasoning and of facts. Truths of reasoning are necessary and their opposites impossible. Facts are contingent and their opposites possible. A necessary truth is known by analysis. | |
| From: Gottfried Leibniz (Monadology [1716], §33) |
| 9344 | Mathematical analysis ends in primitive principles, which cannot be and need not be demonstrated [Leibniz] |
| Full Idea: At the end of the analytical method in mathematics there are simple ideas of which no definition can be given. Moreover there are axioms and postulates, in short, primitive principles, which cannot be demonstrated and do not need demonstration. | |
| From: Gottfried Leibniz (Monadology [1716], §35) | |
| A reaction: My view is that we do not know such principles when we apprehend them in isolation. I would call them 'intuitions'. They only ascend to the status of knowledge when the mathematics is extended and derived from them, and found to work. |
| 2110 | We all expect the sun to rise tomorrow by experience, but astronomers expect it by reason [Leibniz] |
| Full Idea: When we expect it to be day tomorrow, we all behave as empiricists, because until now it has always happened thus. The astronomer alone knows this by reason. | |
| From: Gottfried Leibniz (Monadology [1716], §28) |
| 5987 | Alcmaeon was the first to say the brain is central to thinking [Alcmaeon, by Staden, von] |
| Full Idea: Alcmaeon apparently was the first Greek to assign central cognitive and biological functions to the brain. | |
| From: report of Alcmaeon (fragments/reports [c.490 BCE]) by Heinrich von Staden - Alcmaeon | |
| A reaction: The name of Alcmaeon should be remembered with honour. This was 200 years before Aristotle, who still hadn't worked it out. I presume Alcmaeon inferred the truth from head injuries, which is overwhelming evidence, if you notice it. |
| 2109 | Increase a conscious machine to the size of a mill - you still won't see perceptions in it [Leibniz] |
| Full Idea: If a conscious machine were increased in size, one might enter it like a mill, but we should only see the parts impinging on one another; we should not see anything which would explain a perception. | |
| From: Gottfried Leibniz (Monadology [1716], §17) | |
| A reaction: A wonderful image for capturing a widely held intuition. It seems to motivate Colin McGinn's 'Mysterianism'. The trouble is Leibniz didn't think big/small enough. Down at the level of molecules it might become obvious what a perception is. 'Might'. |
| 19362 | We know the 'I' and its contents by abstraction from awareness of necessary truths [Leibniz] |
| Full Idea: It is through the knowledge of necessary truths and through their abstraction that we rise to reflective acts, which enable us to think of that which is called "I" and enable us to consider that this or that is in us. | |
| From: Gottfried Leibniz (Monadology [1716], §30) | |
| A reaction: For Leibniz, necessary truth can only be known a priori. Sense experience won't reveal the self, as Hume observed. We evidently 'abstract' the idea of 'I' from the nature of a priori thought. Animals have no self (or morals) for this reason. |
| 12707 | The true elements are atomic monads [Leibniz] |
| Full Idea: Monads are the true atoms of nature and, in brief, the elements of things. | |
| From: Gottfried Leibniz (Monadology [1716], (opening)), quoted by Daniel Garber - Leibniz:Body,Substance,Monad 2 | |
| A reaction: Thus in one sentence Leibniz gives us a theory of natural elements, and an account of atoms. This kind of speculation got metaphysics a bad name when science unravelled a more accurate picture. The bones must be picked out of Leibniz. |
| 8388 | Causation is either direct realism, Humean reduction, non-Humean reduction or theoretical realism [Tooley] |
| Full Idea: The main approaches to causation I shall refer to as direct realism, Humean reductionism, non-Humean reductionism, and indirect or theoretical realism. | |
| From: Michael Tooley (Causation and Supervenience [2003], 2) | |
| A reaction: The first simply observes causation (Anscombe), the second reduces it to regularity (Hume), the third reduces it to other natural features (Fair, Salmon, Dowe), the fourth takes an instrumental approach (Armstrong, Tooley). I favour the third approach. |
| 8389 | Causation distinctions: reductionism/realism; Humean/non-Humean states; observable/non-observable [Tooley] |
| Full Idea: The three main distinctions concerning causation are between reductionism and realism; between Humean and non-Humean states of affairs; and between states that are immediately observable and those that are not. | |
| From: Michael Tooley (Causation and Supervenience [2003], 2) | |
| A reaction: I favour reductionism over realism, because I like the question 'If x is real, what is it made of?' I favour non-Humean states of affairs, because I think constant conjunction is very superficial. I presume the existence of non-observable components. |
| 8393 | We can only reduce the direction of causation to the direction of time if we are realist about the latter [Tooley] |
| Full Idea: A reductionist can hold that the direction of causation is to be defined in terms of the direction of time; but this response is only available if one is prepared to adopt a realist view of the direction of time. | |
| From: Michael Tooley (Causation and Supervenience [2003], 4.2.1.2) | |
| A reaction: A nice illustration of the problems that arise if we try to be reductionist about everything. Personally I prefer my realism to be about time rather than about causation. Time, I would say, makes causation possible, not the other way around. |
| 8390 | Causation is directly observable in pressure on one's body, and in willed action [Tooley] |
| Full Idea: The arguments in favour of causation being observable appeal especially to the impression of pressure upon one's body, and to one's introspective awareness of willing, together with the perception of the event which one willed. | |
| From: Michael Tooley (Causation and Supervenience [2003], 3) | |
| A reaction: [He cites Evan Fagels] Anscombe also cites words which have causality built into their meaning. This would approach would give priority to mental causation, and would need to demonstrate that similar things happen out in the world. |
| 8392 | Probabilist laws are compatible with effects always or never happening [Tooley] |
| Full Idea: If laws of causation are probabilistic then the law does not entail any restrictions upon the proportion of events that follow a cause: ...it can have absolutely any value from zero to one. | |
| From: Michael Tooley (Causation and Supervenience [2003], 4.1.3) | |
| A reaction: This objection applies to an account of laws of nature, and also to definitions of causes as events which increase probabilities. One needn't be fully committed to natural necessity, but it must form some part of the account. |
| 8399 | The actual cause may not be the most efficacious one [Tooley] |
| Full Idea: A given type of state may be causally efficacious, but not as efficacious as an alternative states, so it is not true that even a direct cause need raise the probability of its effect. | |
| From: Michael Tooley (Causation and Supervenience [2003], 6.2.4) | |
| A reaction: My intuition is that explaining causation in terms of probabilities entirely misses the point, which mainly concerns explaining the sense of necessitation in a cause. This idea give me a good reason for my intuition. |
| 8391 | In counterfactual worlds there are laws with no instances, so laws aren't supervenient on actuality [Tooley] |
| Full Idea: If a counterfactual holds in a possible world, that is presumably because a law holds in that world, which means there could be basic causal laws that lack all instances. But then causal laws cannot be totally supervenient on the history of the universe. | |
| From: Michael Tooley (Causation and Supervenience [2003], 4.1.2) | |
| A reaction: A nice argument, which sounds like trouble for Lewis. One could deny that the laws have to hold in the counterfactual worlds, but then we wouldn't be able to conceive them. |
| 8394 | Explaining causation in terms of laws can't explain the direction of causation [Tooley] |
| Full Idea: The most serious objection to any account of causation in terms of nomological relations alone is that it can't provide any account of the direction of causation. | |
| From: Michael Tooley (Causation and Supervenience [2003], 5.1) | |
| A reaction: Cf. Idea 8393. I am not convinced that there could be an 'account' of the direction of causation, so I am inclined to take it as given. If we take 'powers' (active properties) as basic, they would have a direction built into them. |
| 8398 | Causation is a concept of a relation the same in all worlds, so it can't be a physical process [Tooley] |
| Full Idea: Against the view that causation is a particular physical process, might it not be argued that the concept of causation is the concept of a relation that possesses a certain intrinsic nature, so that causation must be the same in all possible worlds? | |
| From: Michael Tooley (Causation and Supervenience [2003], 5.4) | |
| A reaction: This makes the Humean assumption that laws of nature might be wildly different. I think it is perfectly possible that physical processes are the only way that causation could occur. Alternatively, the generic definition of 'cause' is just very vague. |
| 2114 | This is the most perfect possible universe, in its combination of variety with order [Leibniz] |
| Full Idea: From all the possible universes God chooses this one to obtain as much variety as possible, but with the greatest order possible; that is, it is the means of obtaining the greatest perfection possible. | |
| From: Gottfried Leibniz (Monadology [1716], §58) |
| 2113 | God alone (the Necessary Being) has the privilege that He must exist if He is possible [Leibniz] |
| Full Idea: God alone (or the Necessary Being) has the privilege that He must exist if He is possible. | |
| From: Gottfried Leibniz (Monadology [1716], §45) |
| 24043 | Soul must be immortal, since it continually moves, like the heavens [Alcmaeon, by Aristotle] |
| Full Idea: Alcmaeon says that the soul is immortal because it resembles immortal things and that this affection belongs to it because it is always in movement, like divine things, such the moon, the sun, the stars and the whole heaven. | |
| From: report of Alcmaeon (fragments/reports [c.490 BCE], DK 24) by Aristotle - De Anima 405a30 | |
| A reaction: Hm. Fish and rivers seem to be continually moving too. Presumably we are like gods, but then Greek gods seem awfully like humans. I don't know the history of belief in immortality; an interesting topic. |