Combining Philosophers

Ideas for Herodotus, [Roman law] and Gottfried Leibniz

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80 ideas

9. Objects / A. Existence of Objects / 2. Abstract Objects / a. Nature of abstracta
Real (non-logical) abstract terms are either essences or accidents [Leibniz]
     Full Idea: Real (as opposed to logical) abstract terms, or at least those which are conceived as real, are either essences or parts of essences, or else accidents (i.e. beings added to a substance).
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], 3.08)
     A reaction: Interesting to refer to accidents as 'beings'. This seems to fit abstraction by ignoring, since you can either ignore the accidents to get the essence, or ignore the essence to get the accidents.
9. Objects / A. Existence of Objects / 2. Abstract Objects / c. Modern abstracta
Wholly uniform things like space and numbers are mere abstractions [Leibniz]
     Full Idea: Things which are uniform, containing no variety, are always mere abstractions: for instance, time, space, and the other entities of pure mathematics.
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], 2.01)
     A reaction: I presume that being 'mere abstractions' denies them ontological status, and makes them creations of thought. If so, I like this idea a lot.
9. Objects / A. Existence of Objects / 5. Simples
The analysis of things leads to atoms of substance, which found both composition and action [Leibniz]
     Full Idea: There are only atoms of substance, that is, real unities absolutely destitute of parts, which are the source of actions, the first absolute principles of the composition of things, and, as it were, the final elements in the analysis of substantial things.
     From: Gottfried Leibniz (New system of communication of substances [1695], p.142)
     A reaction: I like this because it addresses the pure issue of the identity of an individuated object, but also links it with an active view of nature, and not some mere inventory of objects.
9. Objects / A. Existence of Objects / 5. Individuation / a. Individuation
The only way we can determine individuals is by keeping hold of them [Leibniz]
     Full Idea: It is impossible for us to know individuals or to find any way of precisely determining the individuality of any thing except by keeping hold of the thing itself.
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], 3.03)
     A reaction: 'The tallest woman in London' seems to determine someone perfectly well, though only by cross-referencing universal concepts like 'tall'.
Things seem to be unified if we see duration, position, interaction and connection [Leibniz]
     Full Idea: Important relations are duration (order of successive things) and position (order of coexisting things) and interaction. Position without a thing mediating is presence. Beyond these is connection when things move one another. Thus things seem to be one.
     From: Gottfried Leibniz (Letters to Des Bosses [1715], 1712.02.05)
     A reaction: [compressed] This is the best account I can find of his epistemological angle on the unity of things. They are symptoms of the inner power of unification, and he says that God sees these relations most clearly.
Leibniz moved from individuation by whole entity to individuation by substantial form [Leibniz, by Garber]
     Full Idea: By 1680 Leibniz had clearly abandoned the 'whole entity' conception of individuation, for a conception grounded in substantial form alone.
     From: report of Gottfried Leibniz (works [1690]) by Daniel Garber - Leibniz:Body,Substance,Monad 2
     A reaction: In other words, Leibniz became more of an Aristotelian, and more of an essentialist.
9. Objects / A. Existence of Objects / 5. Individuation / b. Individuation by properties
If two individuals could be indistinguishable, there could be no principle of individuation [Leibniz]
     Full Idea: If two individuals were perfectly similar and equal and, in short, indistinguishable in themselves, there would be no principle of individuation.
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], 2.27)
     A reaction: This seems to be the main motive for Leibniz's unusual claim that there cannot be two indiscernible individuals, but it looks suspiciously like an a priori claim made about what should be an a posteriori discovery. Are electrons distinguishable?
The law of the series, which determines future states of a substance, is what individuates it [Leibniz]
     Full Idea: That there should be a persistent law of the series, which involves the future states of that which we conceive to be the same, is exactly what I say constitutes it as the same substance.
     From: Gottfried Leibniz (Letters to Burcher De Volder [1706], 1704), quoted by Richard T.W. Arthur - Leibniz 4 'Applying'
     A reaction: The 'law of the series' is a bit dubious, but it is reasonable to say that a substance is individuated by its coherent progress of change over time. Disjointed change would imply an absence of substance. The law of the series is called 'primitive force'.
9. Objects / A. Existence of Objects / 5. Individuation / c. Individuation by location
We use things to distinguish places and times, not vice versa [Leibniz]
     Full Idea: It is by means of things that we must distinguish one time and place from another, rather than vice versa.
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], 2.27)
     A reaction: This rests on Leibniz's relative view of space (as opposed to Newton's absolute view). If you need to re-identify a thing to individuate it, re-identifying the exact place or time seems impossible, but it is usually manageable with thing.
A body is that which exists in space [Leibniz]
     Full Idea: A body is defined as that which exists in space.
     From: Gottfried Leibniz (Confessio naturae contra atheistas [1669], A6.1.490), quoted by Daniel Garber - Leibniz:Body,Substance,Monad 1
     A reaction: A very early view. Leibniz notes that this tells you nothing about shape and motion.
9. Objects / A. Existence of Objects / 5. Individuation / d. Individuation by haecceity
The laws-of-the-series plays a haecceitist role [Leibniz, by Cover/O'Leary-Hawthorne]
     Full Idea: Leibniz takes the laws-of-the-series to play a haecceitistic role.
     From: report of Gottfried Leibniz (works [1690]) by Cover,J/O'Leary-Hawthorne,J - Substance and Individuation in Leibniz 7.5
     A reaction: Idea 13092 for law-in-the-series. He thinks that a law-in-a-series is unique to a substance, and so can individuate it. That is a pretty good proposal, if anything is going to do the job. Perhaps I do believe in haecceities, as unique bundles of powers?
No two things are quite the same, so there must be an internal principle of distinction [Leibniz]
     Full Idea: In addition to the difference of time or of place there must always be an internal principle of distinction: although there can be many things of the same kind, it is still the case that none of them are ever exactly alike.
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], 2.27)
     A reaction: This rests on Leibniz's unusual view that all things (even electrons) are qualitatively distinct. Personally I disagree with that, but agree with the idea. Things have time and place because they have identity, not the other way around.
9. Objects / A. Existence of Objects / 6. Nihilism about Objects
Fluidity is basic, and we divide into bodies according to our needs [Leibniz]
     Full Idea: Fluidity is the fundamental condition, and the division into bodies is carried out - there being no obstacle to it - according to our need.
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], 2.13)
     A reaction: Leibniz is referring to what he usually calls 'aggregates', like piles of bricks, which are things lacking a unifying substance. There may be no true substances, in which fluidity is the order of the day.
9. Objects / B. Unity of Objects / 1. Unifying an Object / a. Intrinsic unification
Philosophy needs the precision of the unity given by substances [Leibniz]
     Full Idea: Philosophy cannot be better reduced to something precise, than by recognising only substances or complete beings endowed with a true unity, with different states that succeed one another; all else is phenomena, abstractions or relations.
     From: Gottfried Leibniz (Letters to Antoine Arnauld [1686], 1687.04.30), quoted by Daniel Garber - Leibniz:Body,Substance,Monad 7
     A reaction: This idea bothers me. Has the whole of modern philosophy been distorted by this yearning for 'precision'? It has put mathematicians and logicians in the driving seat. Do we only attribute unity because it suits our thinking?
Identity of a substance is the law of its persistence [Leibniz]
     Full Idea: For there to be a certain persisting law which involves the future states of that which we conceive as one and the same continuant, this is what I say constitute's a substance's identity.
     From: Gottfried Leibniz (works [1690], G II:264), quoted by David Wiggins - Sameness and Substance 3.1
     A reaction: This is a key remark for those who thing 'persistence conditions' are basic to metaphysics. I'm not so sure.
9. Objects / B. Unity of Objects / 1. Unifying an Object / b. Unifying aggregates
A body would be endless disunited parts, if it did not have a unifying form or soul [Leibniz]
     Full Idea: Without soul or form of some kind, a body would have no being, because no part of it can be designated which does not in turn consist of more parts. Thus nothing could be designated in a body which could be called 'this thing', or a unity.
     From: Gottfried Leibniz (Conspectus libelli (book outline) [1678], A6.4.1988), quoted by Daniel Garber - Leibniz:Body,Substance,Monad 1
     A reaction: The locution 'soul or form' is disconcerting, and you have to spend some time with Leibniz to get the hang of it. The 'soul' is not intelligent, and is more like a source of action and response.
Accidental unity has degrees, from a mob to a society to a machine or organism [Leibniz]
     Full Idea: There are degrees of accidental unity, and an ordered society has more unity than a chaotic mob, and an organic body or a machine has more unity than a society.
     From: Gottfried Leibniz (Letters to Antoine Arnauld [1686], 1687.04.30)
     A reaction: This immediately invites questions about the extremes. Why does the very highest degree of 'accidental unity' not achieve 'true unity'? And why cannot a very ununified aggregate have a bit of unity (as in unrestricted mereological composition)?
9. Objects / B. Unity of Objects / 1. Unifying an Object / c. Unity as conceptual
We find unity in reason, and unity in perception, but these are not true unity [Leibniz]
     Full Idea: A pair of diamonds is merely an entity of reason, and even if one of them is brought close to another, it is an entity of imagination or perception, that is to say a phenomenon; contiguity, common movement and the same end don't make substantial unity.
     From: Gottfried Leibniz (Letters to Antoine Arnauld [1686], 1687.04.30), quoted by Daniel Garber - Leibniz:Body,Substance,Monad 7
     A reaction: This invites the question of what you have to do to two objects to give them substantial unity. The distinction between unity 'of reason' and unity 'of perception' is good.
Leibniz bases pure primitive entities on conjunctions of qualitative properties [Leibniz, by Adams,RM]
     Full Idea: Leibniz is committed with apparent consistency to both a purely qualitative character of all thisnesses, and to primitiveness of individual identity. He regards thisnesses as conjunctions of simpler, logically independent suchnesses.
     From: report of Gottfried Leibniz (works [1690]) by Robert Merrihew Adams - Primitive Thisness and Primitive Identity 5
     A reaction: Hence Leibniz is held to say that all of the qualitative properties are 'essential' to the object, since all of them are needed to constitute its identity. Hence absolutely nothing about an object, even an electron, could be different, which is daft.
To exist and be understood, a multitude must first be reduced to a unity [Leibniz]
     Full Idea: A plurality of things can neither be understood nor can exist unless one first understands the thing that is one, that to which the multitude necessarily reduces.
     From: Gottfried Leibniz (Notes on Comments by Fardella [1690], Prop 3)
     A reaction: Notice that it is our need to understand which imposes the unity on the multitude. It is not just some random fiction, or a meaningless mechanical act of thought.
9. Objects / B. Unity of Objects / 2. Substance / a. Substance
The complete notion of a substance implies all of its predicates or attributes [Leibniz]
     Full Idea: The nature of an individual substance or of a complete being is to have a notion so complete that it is sufficient to contain and to allow us to deduce from it all the predicates of the subject to which this notion is attributed.
     From: Gottfried Leibniz (Discourse on Metaphysics [1686], §8)
     A reaction: This is the unusual Leibnizian view of such things, which he takes to extremes. I think it depends on whether you are talking of predicates, or of real intrinsic properties. I don't see how what happens to a substance can be contained in the subject.
A body is a unified aggregate, unless it has an indivisible substance [Leibniz]
     Full Idea: One will never find a body of which it may be said that it is truly one substance, ...because entities made up by aggregation have only as much reality as exists in the constituent parts. Hence the substance of a body must be indivisible.
     From: Gottfried Leibniz (Letters to Antoine Arnauld [1686], 1686.11)
     A reaction: Leibniz rejected atomism, and he evidently believed that pure materialists must deny the real existence of physical objects. Common sense suggests that causal bonds bestow a high degree of unity on bodies (if degrees are allowed).
Unity needs an indestructible substance, to contain everything which will happen to it [Leibniz]
     Full Idea: Substantial unity requires a complete, indivisible and naturally indestructible entity, since its concept embraces everything that is to happen to it, which cannot be found in shape or motion.
     From: Gottfried Leibniz (Letters to Antoine Arnauld [1686], 1686.11.28/12.8)
     A reaction: Hence if a tile is due to be broken in half (Arnauld's example), it cannot have had unity in the first place. To what do we refer when we say 'the tile was broken'?
Every bodily substance must have a soul, or something analogous to a soul [Leibniz]
     Full Idea: Every bodily substance must have a soul, or at least an entelechy which is analogous to the soul.
     From: Gottfried Leibniz (Letters to Antoine Arnauld [1686], 1687.10.09)
     A reaction: He routinely commits to a 'soul', and then pulls back and says it may only be an 'analogy'. He had deep doubts about his whole scheme, which emerged in the late correspondence with Des Bosses. This not monads, says Garber.
The concept of forces or powers best reveals the true concept of substance [Leibniz]
     Full Idea: The concept of forces or powers ..for whose explanation I have set up a distinct science of dynamics, brings the strongest light to bear upon our understanding of the true concept of substance.
     From: Gottfried Leibniz (De primae philosophiae emendatione [1694], G IV 469), quoted by Daniel Garber - Leibniz:Body,Substance,Monad 4
     A reaction: My own experience was that as soon as I encountered the notion of a 'power' in the metaphysics of science (see Molnar on this) the whole thing began to form a coherent picture. Powers rule.
The notion of substance is one of the keys to true philosophy [Leibniz]
     Full Idea: I consider the notion of substance to be one of the keys to the true philosophy. ....I imagine that philosophers will one day know the notion of substance a bit better than they do now.
     From: Gottfried Leibniz (Letters to Thomas Burnett [1703], 1699.01.20/30)
     A reaction: This is a controversial remark at this historical moment, when the apparent Aristotelian commitment to substances was becoming discredited. Personally I would eliminate substance, but not just because physicists don't refer to it.
Individuality is in the bond substance gives between past and future [Leibniz]
     Full Idea: Within each substance there is a perfect bond between the future and the past, which is what creates the identity of the individual.
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], 2.01)
     A reaction: I'm not quite sure if this means anything, but the idea that a bond across time is a necessity for intrinsic identity is interesting. The 'bond' would, I take it, have to be a causal one.
Every substance is alive [Leibniz]
     Full Idea: Every substance is alive.
     From: Gottfried Leibniz (Letters to Des Bosses [1715], 1712.02.05)
     A reaction: The most charitable interpretation of this is that substances are what have unity, and the best model of unity that we can grasp is the unity of an organism. The less charitable view is that he literally thinks a pebble is 'alive'. Hm.
9. Objects / B. Unity of Objects / 2. Substance / b. Need for substance
Aggregates don’t reduce to points, or atoms, or illusion, so must reduce to substance [Leibniz]
     Full Idea: In aggregates one must necessarily arrive either at mathematical points from which some make up extension, or at atoms (which I dismiss), or else no reality can be found in bodies, or finally one must recognises substances that possess a true unity.
     From: Gottfried Leibniz (Letters to Antoine Arnauld [1686], 1687.04.30), quoted by Daniel Garber - Leibniz:Body,Substance,Monad 2
     A reaction: Garber calls this Leibniz's Aggregate Argument. Leibniz is, of course, talking of physical aggregates which have unity. He consistently points out that a pile of logs has no unity at all. But is substance just that-which-provides-unity?
9. Objects / B. Unity of Objects / 2. Substance / c. Types of substance
Substances mirror God or the universe, each from its own viewpoint [Leibniz]
     Full Idea: Each substance is like a whole world, and like a mirror of God, or indeed of the whole universe, which each one expresses in its own fashion.
     From: Gottfried Leibniz (Discourse on Metaphysics [1686]), quoted by Nicholas Jolley - Leibniz Intro
     A reaction: Leibniz isn't a pantheist, so he does not identify God with the universe, so it is a bit revealing that substance could reflect either one or the other, and he doesn't seem to care which. In the end, for all the sophistication, he just made it up.
Substances are everywhere in matter, like points in a line [Leibniz]
     Full Idea: There are substances everywhere in matter, just as points are everywhere in a line.
     From: Gottfried Leibniz (Notes on Comments by Fardella [1690], Clarif)
     A reaction: Since Leibniz is unlikely to believe in the reality of the points, we must wonder whether he was really committed to this infinity of substances. The more traditional notion of substance is always called 'substantial form' by Leibniz.
Substance must necessarily involve progress and change [Leibniz]
     Full Idea: The nature of substance necessarily requires and essentially involves progress or change, without which it would not have the force to act.
     From: Gottfried Leibniz (New system of communication of substances [1695], p.144)
     A reaction: Bravo. Most metaphysical musings regarding 'substance' seem entirely wrapped up in the problem of pure identity, and forget about the role of objects in activity and change.
9. Objects / B. Unity of Objects / 2. Substance / d. Substance defined
Substance is that which can act [Leibniz]
     Full Idea: I define substance as that which can act.
     From: Gottfried Leibniz (Definitiones cogitationesque metaphysicae [1678], A6.4.1398), quoted by Daniel Garber - Leibniz:Body,Substance,Monad 3
     A reaction: This is in tune with the notion that to exist is to have causal powers. I find the view congenial, and the middle period of Leibniz's thought, before monads became too spiritual, chimes in with my view.
Leibnizian substances add concept, law, force, form and soul [Leibniz, by Cover/O'Leary-Hawthorne]
     Full Idea: To the traditional idea of substance (independent, subjects of predication, active, persistent) Leibniz adds, distinctively, complete individual concept, law-of-the-series, active force, form and soul or entelechy.
     From: report of Gottfried Leibniz (works [1690]) by Cover,J/O'Leary-Hawthorne,J - Substance and Individuation in Leibniz 6.1.1
     A reaction: 'Form' seems to be Aristotelian, and 'soul' seems ridiculous. I don't think the 'complete concept' is much help. However, the 'law-in-the-series' is very interesting (Idea 13079), if employed sensibly, and 'active force' is spot-on. Powers define reality.
Substances cannot be bare, but have activity as their essence [Leibniz]
     Full Idea: I maintain that substances (material or immaterial) cannot be conceived in their bare essence devoid of activity; that activity is of the essence of substance in general
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], Pref 65)
     A reaction: Leibniz liked the idea that God was the source of this activity, but this remark makes Leibniz a direct ancestor of modern scientific essentialism.
Substance is a force for acting and being acted upon [Leibniz]
     Full Idea: The very substance in things consists of a force for acting and being acted upon.
     From: Gottfried Leibniz (On Nature Itself (De Ipsa Natura) [1698], §08)
     A reaction: Garber places this text just before the spiritual notion of monads took a grip on Leibniz. He seems to have thought that only some non-physical entity, with appetite and perception, could generate force. Wrong.
Substances are essentially active [Leibniz, by Jolley]
     Full Idea: For Leibniz, it is the very essence of substances to be sources of activity.
     From: report of Gottfried Leibniz (works [1690]) by Nicholas Jolley - Leibniz Ch.2
     A reaction: This makes the views of Leibniz sympathetic to modern essentialism (of which I am a fan), because it places active power at the centre of what it is to exist, rather than action being imposed on matter which is otherwise passive.
9. Objects / B. Unity of Objects / 2. Substance / e. Substance critique
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.
9. Objects / B. Unity of Objects / 3. Unity Problems / d. Coincident objects
We can imagine two bodies interpenetrating, as two rays of light seem to [Leibniz]
     Full Idea: We find that two shadows or two rays of light interpenetrate, and we could devise an imaginary world where bodies did the same.
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], 2.27)
     A reaction: I suspect this is a case of being able to imagine something when you don't fully understand it (like a bonfire on the Moon), but when you fully understand the modern physics of it, you see the necessity of separation between objects.
9. Objects / B. Unity of Objects / 3. Unity Problems / e. Vague objects
The essence of baldness is vague and imperfect [Leibniz]
     Full Idea: There are vague and imperfect essences, as in the question of how few hairs a man can have without being bald.
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], 3.05)
     A reaction: This example is much discussed in contemporary debate, but I now learn that it has a venerable history. The surprise here is the word 'essences', because I had taken Leibnizian essences to be 'perfect ideas', and hence precise.
9. Objects / C. Structure of Objects / 2. Hylomorphism / b. Form as principle
Forms are of no value in physics, but are indispensable in metaphysics [Leibniz]
     Full Idea: The consideration of forms serves no purpose in the details of physics and must not be used to explain particular phenomena. …but their misuse must not lead us to reject something which is so useful to metaphysics.
     From: Gottfried Leibniz (Discourse on Metaphysics [1686], 10), quoted by Robert Pasnau - Metaphysical Themes 1274-1671 24.5
     A reaction: This is a key test for the question of whether metaphysics is separate from science (as Leibniz and Pasnau think), or whether there is a continuum. Is 'substantial form' an illuminating way to undestand modern physics?
9. Objects / C. Structure of Objects / 2. Hylomorphism / c. Form as causal
Leibniz strengthened hylomorphism by connecting it to force in physics [Leibniz, by Garber]
     Full Idea: A standard criticism of the scholastic notions of matter and form is that they are obscure and unintelligible. But in Leibniz's system they are connected directly with notions of active and passive force that play an intelligible roles in his physics.
     From: report of Gottfried Leibniz (works [1690]) by Daniel Garber - Leibniz:Body,Substance,Monad 4
     A reaction: This seems to me to be very appealing. Aristotle was clearly on the right lines, but just ran out of things to say, once he had pointed in the right direction. Maybe 'fields' and 'strings' can fill out the Aristotelian conception of form.
9. Objects / C. Structure of Objects / 2. Hylomorphism / d. Form as unifier
Form or soul gives unity and duration; matter gives multiplicity and change [Leibniz]
     Full Idea: Substantial form, or soul, is the principle of unity and duration, matter is that of multiplicity and change
     From: Gottfried Leibniz (Conspectus libelli (book outline) [1678], A6.4.1398-9), quoted by Daniel Garber - Leibniz:Body,Substance,Monad 2
     A reaction: Leibniz was a fan of the unfashionable Aristotle, and tried to put a spin on his views consonant with contemporary Hobbesian mechanistic views. Oddly, he likes the idea that 'form' is indestructable, which I don't understand.
9. Objects / C. Structure of Objects / 7. Substratum
A 'substratum' is just a metaphor for whatever supports several predicates [Leibniz]
     Full Idea: From the beginning we conceive several predicates in a single subject, and that is all there is to these metaphorical words 'support' and 'substratum'. So I do not see why it is made out to involve a problem.
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], 2.23)
     A reaction: The question is whether the substratum is 'bare' if you remove all the predicates, and clearly Leibniz believes you are left with true essential substance (although the removal process is presumably only possible in thought, thanks to God).
9. Objects / C. Structure of Objects / 8. Parts of Objects / a. Parts of objects
Indivisibles are not parts, but the extrema of parts [Leibniz]
     Full Idea: Indivisibles are not parts, but the extrema of parts.
     From: Gottfried Leibniz (Pacidius Philalethi dialogue [1676], A6.3.565-6), quoted by Daniel Garber - Leibniz:Body,Substance,Monad 1
     A reaction: This is incipient monadology, that the bottom level of division ceases to be parts of a thing, and arrives at a different order of entity, to explain the parts of things. Leibniz denies that this subdivision comes down to points.
9. Objects / D. Essence of Objects / 1. Essences of Objects
The essence of a circle is the equality of its radii [Leibniz]
     Full Idea: The essence of a circle consists in the equality of all lines drawn from its centre to its circumference.
     From: Gottfried Leibniz (Letters to Thomasius [1669], 1669)
     A reaction: Compare Locke in Idea 13431 and Spinoza in Idea 13073 on the essence of geometrical figures. A key question is whether the essence is in the simplest definition, or in a complex and wide-ranging account, e.g. including conic sections for circles.
Subjects include predicates, so full understanding of subjects reveals all the predicates [Leibniz]
     Full Idea: The subject-term must always include the predicate-term, in such a way that the man who understood the notion of the subject perfectly would also judge that the predicate belongs to it.
     From: Gottfried Leibniz (Discourse on Metaphysics [1686], §8)
     A reaction: Sounds as if every sentence is analytic, but he doesn't mean that. He does, oddly, mean that if we fully understand the name 'Alexander', we understand his complete history, which is a bit silly, I'm afraid. Even God doesn't learn things just from names.
Basic predicates give the complete concept, which then predicts all of the actions [Leibniz]
     Full Idea: Apart from those that depend on others, one must only consider together all the basic predicates in order to form the complete concept of Adam adequate to deduce from it everything that is ever to happen to him, as much as is necessary to account for it.
     From: Gottfried Leibniz (Letters to Antoine Arnauld [1686], 1686.06)
     A reaction: This (implausibly) goes beyond mere prediction of properties. Eve's essence seems to be relevant to Adam's life. Note that the complete concept is not every predicate, but only those 'necessary' to predict the events. Cf Idea 13082.
Essences exist in the divine understanding [Leibniz]
     Full Idea: Essences exist in the divine understanding before one considers will.
     From: Gottfried Leibniz (Letters to Antoine Arnauld [1686], 1686.07.4/14 X)
     A reaction: This is a sort of religious neo-platonism. The great dream seems to be that of mind-reading God, and the result is either Pythagoras (it's numbers!), or Plato (it's pure ideas!), or this (it's essences!). See D.H.Lawrence's poem on geranium and mignottes.
A true being must (unlike a chain) have united parts, with a substantial form as its subject [Leibniz]
     Full Idea: In a Being one per se a real union is required consisting not in the situation or motion of parts, as in a chain or a house, but in a unique individual principle and subject of attributes and operations, in us a soul and in a body a substantial form.
     From: Gottfried Leibniz (De Mundo Praesenti [1686], A6.4.1506), quoted by Daniel Garber - Leibniz:Body,Substance,Monad 7
     A reaction: Leibniz is said not to be an essentialist, by making all properties essential, but he is certainly committed to substance, and it sounds like essence here (or one view of essence), when it makes identity possible. This idea is pure Aristotle.
9. Objects / D. Essence of Objects / 3. Individual Essences
Particular truths are just instances of general truths [Leibniz]
     Full Idea: The reasons for particular truths rest wholly on the more general ones of which they are mere instances.
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], 1.01)
     A reaction: Clearly particulars have their own distinctive truth, but the Leibniz case seems to be that a particular is a unique intersection for an array of general truths - and nothing else. Audrey Hepburn's smile has no generalities to it.
We can't know individuals, or determine their exact individuality [Leibniz]
     Full Idea: It is impossible for us to have knowledge of individuals and to find the means of determining exactly the individuality of everything.
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], 3.3)
     A reaction: Aristotle was clearly also tempted by this doubt (since universals are involved), though individuals are what he wanted to understand. I think they are wrong. Leibniz gives the bizarre reason that we can't know individuals as they each contain infinity.
9. Objects / D. Essence of Objects / 4. Essence as Definition
Essence is just the possibility of a thing [Leibniz]
     Full Idea: Essence is fundamentally nothing but the possibility of the thing under consideration. Something which is thought possible is expressed by a definition.
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], 3.03)
     A reaction: It is unclear whether he means 'possible modes of existence' or 'possible actions of the thing'. Leibniz sees more clearly than Aristotle that essences extend beyond the actual thing, because Leibniz is more aware of the active powers.
9. Objects / D. Essence of Objects / 6. Essence as Unifier
Bodies need a soul (or something like it) to avoid being mere phenomena [Leibniz]
     Full Idea: Every substance is indivisible and consequently every corporeal substance must have a soul or at least an entelechy which is analogous to the soul, since otherwise bodies would be no more than phenomena.
     From: Gottfried Leibniz (Letters to Antoine Arnauld [1686], G II 121), quoted by Daniel Garber - Leibniz:Body,Substance,Monad 2
     A reaction: There is a large gap between having 'a soul' and having something 'analogous to a soul'. I take the analogy to be merely as originators of action. Leibniz wants to add appetite and sensation to the Aristotelian forms (but knows this is dubious!).
A substantial bond of powers is needed to unite composites, in addition to monads [Leibniz]
     Full Idea: Some realising thing must bring it about that composite substance contains something substantial besides monads, otherwise composites will be mere phenomena. The scholastics' active and passive powers are the substantial bond I am urging.
     From: Gottfried Leibniz (Letters to Des Bosses [1715], 1716.01.13), quoted by Daniel Garber - Leibniz:Body,Substance,Monad 9
     A reaction: [compressed] This appears to be a major retreat, in the last year of Leibniz's life, from the full monadology he had espoused. How do monads connect to matter, and thus unify it? He is returning to Aristotelian hylomorphism.
9. Objects / D. Essence of Objects / 7. Essence and Necessity / a. Essence as necessary properties
The essence is the necessary properties, and the concept includes what is contingent [Leibniz]
     Full Idea: Of the essence of a particular thing is what pertains to it necessarily and perpetually; of the concept of an individual thing on the other hand is what pertains to it contingently or per accidens.
     From: Gottfried Leibniz (Human Freedom and Divine choice [1690], Grua 383), quoted by Cover,J/O'Leary-Hawthorne,J - Substance and Individuation in Leibniz 3.3.1
     A reaction: This arbitrates on the apparent conflict between his remarks in Idea 13077 and Idea 10382. There seems to be a distinction between the 'concept' of a thing, and the 'complete concept', the latter including the contingent properties.
9. Objects / D. Essence of Objects / 7. Essence and Necessity / b. Essence not necessities
The complete concept of an individual includes contingent properties, as well as necessary ones [Leibniz]
     Full Idea: In this complete concept of possible Peter are contained not only essential or necessary things, ..but also existential things, or contingent items included there, because the nature of an individual substance is to have a perfect or complete concept.
     From: Gottfried Leibniz (Of liberty, Fate and God's grace [1690], Grua 311), quoted by Cover,J/O'Leary-Hawthorne,J - Substance and Individuation in Leibniz 3.3.1
     A reaction: Compare Idea 13077, where he seems to say that the complete concept is only necessarily linked to properties which will predict future events - though I suppose that would have to include all of the contingent properties mentioned here.
A necessary feature (such as air for humans) is not therefore part of the essence [Leibniz]
     Full Idea: That which is necessary for something does not constitute its essence. Air is necessary for our life, but our life is something other than air.
     From: Gottfried Leibniz (Letters to Queen Charlotte [1702], 1702)
     A reaction: Bravo. Why can't modern philosophers hang on to this distinction? They seem to think that because they don't believe in traditional essences they can purloin the word for something else. Same with the word 'abstraction'.
9. Objects / D. Essence of Objects / 8. Essence as Explanatory
If you fully understand a subject and its qualities, you see how the second derive from the first [Leibniz]
     Full Idea: Every time we find some quality in a subject, we ought to think that, if we understood the nature of this subject and of this quality, we should conceive how this quality could result from it.
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], Pref)
     A reaction: Thus (in Kripke's analogy) God cannot make 'subjects' on Thursday and then add 'qualities' on Friday. Add the point that all subjects are physical, and I say you have the whole story. The physical entails the mental. The laws result from the qualities.
9. Objects / D. Essence of Objects / 9. Essence and Properties
The properties of a thing flow from its essence [Leibniz]
     Full Idea: It is the same to look for perfection in an essence and in the properties that flow from an essence.
     From: Gottfried Leibniz (Letters to Wolff [1715], 1715.05.18)
     A reaction: It is helpful to have Leibniz spelling out his commitment to the traditional view of essence, as that from which the more evident properties flow.
Leibniz's view (that all properties are essential) is extreme essentialism, not its denial [Leibniz, by Mackie,P]
     Full Idea: The view standardly attributed to Leibniz, that makes all an individual's properties essential to it should be regarded as an extreme version of essentialism, not a denial of essentialism.
     From: report of Gottfried Leibniz (works [1690]) by Penelope Mackie - How Things Might Have Been 1.1
     A reaction: Wiggins disagrees, saying that Leibniz was not an essentialist, which is an interesting topic of research for those who are interested. I would take Leibniz to be not an essentialist, on that basis, as essentialism makes a distinction. See Quine on that.
9. Objects / D. Essence of Objects / 10. Essence as Species
Truths about species are eternal or necessary, but individual truths concern what exists [Leibniz]
     Full Idea: The concept of a species contains only eternal or necessary truths, whereas the concept of an individual contains, regarded as possible, what in fact exists or what is related to the existence of things and to time.
     From: Gottfried Leibniz (Letters to Antoine Arnauld [1686], 1686.06)
     A reaction: This seems to be what is behind the preference some have for kind-essences rather than individual essences. But the individual must be explained, as well as the kind. Not all tigers are identical. The two are, of course, compatible.
For some sorts, a member of it is necessarily a member [Leibniz]
     Full Idea: There are sorts or species such that if an individual has ever been of such a sort or species it cannot (naturally, at least) stop being of it.
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], 3.06)
     A reaction: Note the thoughtful 'naturally, at least', which blocks genetic engineering. But natural selection is genetic engineering. Crucially, Leibniz is not attributing this to all sorts or species, and allows exceptions.
9. Objects / D. Essence of Objects / 12. Essential Parts
The same whole ceases to exist if a part is lost [Leibniz]
     Full Idea: We cannot say - with complete fidelity to the truth of things - that the same whole continues to exist if a part of it is lost.
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], 2.27.11)
     A reaction: This is the reference Simons 1987:319 gives when he claims that Leibniz accepts mereological essentialism. I think this is mereological necessity of identity, but not what I call 'essentialism'. That has to distinguish essential from non-essential.
A composite substance is a mere aggregate if its essence is just its parts [Leibniz]
     Full Idea: An aggregate, but not a composite substance, is resolved into parts. A composite substance only needs the coming together of parts, but is not essentially constituted by them, otherwise it would be an aggregate.
     From: Gottfried Leibniz (Letters to Des Bosses [1715], 1716.05.29)
     A reaction: The point is that there is more to some things than there mere parts. Only some unifying principle, in addition to the mere parts, bestows a unity. Mereology is a limited activity if it has nothing to say about this issue.
9. Objects / D. Essence of Objects / 13. Nominal Essence
We have a distinct idea of gold, to define it, but not a perfect idea, to understand it [Leibniz]
     Full Idea: That gold is a metal which resists cupellation and is insoluble in aquafortis is a distinct idea, for it gives us the criteria or definition of 'gold'. But it is not a perfect idea, because we know too little about cupellation and actions of aquafortis.
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], 2.31)
     A reaction: This connects the 'perfect idea' of something with knowing its active substance, and hence its essence. See Idea 12976 for the connection between perfect ideas and definitions.
If two people apply a single term to different resemblances, they refer to two different things [Leibniz]
     Full Idea: If one person applies the name 'avarice' to one resemblance, and some one else to another, there will be two different species designated by the same name.
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], 6.6.292), quoted by Nicholas Jolley - Leibniz and Locke on Essences p.199
     A reaction: Part of Leibniz's sustained attack on Locke's nominal essences. There is clearly an uninteresting nominal essence, where a 'big brown bear' is necessarily brown, but in the interesting respects I think Leibniz is right.
Locke needs many instances to show a natural kind, but why not a single instance? [Leibniz, by Jolley]
     Full Idea: Leibniz points out that it is a concealed premise of Locke's argument that if a natural kind exists it must have many instances, but there seems no a priori objection to the idea of a species with just one member.
     From: report of Gottfried Leibniz (New Essays on Human Understanding [1704], 6.6.311) by Nicholas Jolley - Leibniz and Locke on Essences p.200
     A reaction: I can't see this bothering Locke. Generally we formulate nominal essences by induction from bundles of ideas, but we can formulate a cautious first stab at it from one instance. If you see a new creature, is it a normal one, or a 'monster'?
9. Objects / D. Essence of Objects / 14. Knowledge of Essences
Essence is the distinct thinkability of anything [Leibniz]
     Full Idea: (Essence) is the distinct thinkability (cogitabilitas) of anything.
     From: Gottfried Leibniz (Notes on John Wilkins [1672], A6.2.487-8), quoted by Daniel Garber - Leibniz:Body,Substance,Monad 1
     A reaction: A very original remark from the young Leibniz. It is neutral as to whether this is a real feature of objects, or a feature of human mental capacities. Presumably accidental features are thinkable, so 'distinct' is the key word.
9. Objects / D. Essence of Objects / 15. Against Essentialism
Leibniz was not an essentialist [Leibniz, by Wiggins]
     Full Idea: Leibniz was not an essentialist.
     From: report of Gottfried Leibniz (works [1690]) by David Wiggins - Sameness and Substance Renewed 4.2 n4
     A reaction: Assuming this is right, it is rather helpful, because you can read mountains of Leibniz without ever being quite sure. Mackie says he IS an extreme essentialist, treating all properties as essential. Wiggins makes more sense there.
9. Objects / E. Objects over Time / 1. Objects over Time
Changeable accidents are modifications of unchanging essences [Leibniz]
     Full Idea: Everything accidental or changeable ought to be a modification of something essential or perpetual.
     From: Gottfried Leibniz (Letters to Burcher De Volder [1706], 1704.06.30)
     A reaction: Clear evidence that Leibniz is very much a traditional Aristotelian essentialist, and not as modal logicians tend to characterise him, as a super-essentialist who thinks all properties are essential. They are necessary for identity, but that's different.
9. Objects / E. Objects over Time / 9. Ship of Theseus
Bodies, like Theseus's ship, are only the same in appearance, and never strictly the same [Leibniz]
     Full Idea: We must acknowledge that organic bodies as well as others remain 'the same' only in appearance, and not strictly speaking. It is rather like the river whose water is continually changing, or like Theseus's ship which Athenians constantly repaired.
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], 2.27)
     A reaction: This is Leibniz's standard view, that something only remains the same if it has a unifying substance, and so a collection of planks is just an aggregate, and doesn't have any identity to begin with.
9. Objects / F. Identity among Objects / 1. Concept of Identity
Inequality can be brought infinitely close to equality [Leibniz]
     Full Idea: Equality may be considered as an infinitely small inequality, and we may make inequality approach equality as much as we wish.
     From: Gottfried Leibniz (A General Principle to Explain Laws of Nature [1687], p.67)
     A reaction: An interesting response to David Lewis's brusque dismissal of the problem of identity, as all-or-nothing...end of story.
9. Objects / F. Identity among Objects / 7. Indiscernible Objects
Two eggs can't be identical, because the same truths can't apply to both of them [Leibniz]
     Full Idea: It isn't possible to have two particulars that are similar in all respects - for example two eggs - for it is necessary that some things can be said about one of them that cannot be said about the other, else they could be substituted for one another.
     From: Gottfried Leibniz (works [1690]), quoted by David Wiggins - Sameness and Substance 2.2
     A reaction: [from a 'fragment' for which Wiggins gives a reference] This quotation doesn't rest the distinctness of the eggs on some intrinsic difference, but on the fact that we can say different things about the two eggs.
No two things are totally identical [Leibniz]
     Full Idea: By virtue of insensible variations, two individual things can never be perfectly alike.
     From: Gottfried Leibniz (New Essays on Human Understanding [1704], Pref)
     A reaction: This sounds a bit like the 'discernibility of non-identicals', except that he says that the differences may not be 'sensible'. He has to be talking of physical things, since I presume that, say, the symmetry of two circles is perfectly identical.
Things in different locations are different because they 'express' those locations [Leibniz]
     Full Idea: Things that differ in place must express their place, that is, they must express the things surrounding, and thus they must be distinguished not only by place, that is, not by an extrinsic denomination alone, as is commonly thought.
     From: Gottfried Leibniz (Letters to Burcher De Volder [1706], 1703.06.20)
     A reaction: This is an unusual view, which has some attractions, as it enables the relations of a thing to individuate it, while maintaining that this is a real difference in character.
In nature there aren't even two identical straight lines, so no two bodies are alike [Leibniz]
     Full Idea: In nature any straight line you may take is individually different from any other straight line you may find. Accordingly, it cannot come about that two bodies are perfectly equal and alike.
     From: Gottfried Leibniz (Letters to Burcher De Volder [1706], 1703.06.20)
     A reaction: Leibniz was very good at persuasive examples! It remains unclear, though, why he takes the Identity of Indiscernibles to be a necessary truth, when he seems to have only observed it from experience. This is counter to his other principles.
If two bodies only seem to differ in their position, those different environments will matter [Leibniz]
     Full Idea: If two bodies differ only in their position, their individual relations to the environment must be taken into account, so that more is involved in their distinguishability than just position.
     From: Gottfried Leibniz (Letters to Burcher De Volder [1706], 1703.06.20)
     A reaction: This seems to allow that two bodies could be intrinsically type-identical (though differing in extrinsic features), which is contrary to his normal view. I suppose a different location in the gravitational field will make an intrinsic difference.
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?
9. Objects / F. Identity among Objects / 9. Sameness
Things are the same if one can be substituted for the other without loss of truth [Leibniz]
     Full Idea: Leibniz's definition is as follows: Things are the same as each other, of which one can be substituted for the other without loss of truth ('salva veritate').
     From: Gottfried Leibniz (works [1690]), quoted by Gottlob Frege - Grundlagen der Arithmetik (Foundations) §65
     A reaction: Frege doesn't give a reference. (Anyone know it?). This famous definition is impressive, but has problems when the items being substituted appear in contexts of belief. 'Oedipus believes Jocasta (his mother!) would make a good wife'.