Dear Paul,

I am not a professional Leibniz scholar either but studying Leibniz is what I do much of the time and I shall be talking on the relation of Leibniz's metaphysics to modern physics at the Tercentenary Conference on the Monadology in Edinburgh in May. I think Michael's quote may well be the source for this. Leibniz says similar things many times in many manuscripts so it may be elsewhere as well.

One caution I would make is in the term 'whole'. What Leibniz is saying here, and it is his view, but maybe phrased in a way intended to be easy for a correspondent to understand, is that 'things' or objects or 'bodies' do not really exist as entities but are merely appearances of aggregates (of monadic entities). Some bodies, such as animals, (but he thinks probably not ceramic tiles) do have associated real entities which are their dominant monads but monads are entirely dynamic relational entities and do not themselves appear (individually) as 'matter'. So a cat as an object is merely an appearance of many component monadic elements but a cat also has a dominant dynamic spirit or soul which determines its actions but is invisible.

The point here is that the thing is not really a 'whole' - only as an idea in our head is it an entity. As a material body it is merely an appearance arising from an aggregate of units that may be thought of as parts of this **purely notional** quasi-entity. The relevance of this is that Leibniz denies that any real entity can have **any parts** because all real entities are indivisible and monadic. So it seems that Leibniz is using 'parts' here to help the reader but he is not wanting us to think that these are parts of a real 'whole'.

I apologise if that is a bit tortuous but this particular aspect of Leibniz's metaphysics causes a lot of confusion. Part of the problem is that up until about 1695 he recognised 'corporeal substances' in the sense of material entities. But by the Monadology of 1714 he had, it seems, decided that the only real entities existing in their own right (substances as they were called) were non-material dynamic monads. So in a sense by this stage he no longer recognises what a lot of people would call 'physical things'. Everything is purely dynamic and ideational. Unfortunately, towards the end of Monadology he makes it sound as if there still are bodies 'progressing in harmony' with individual monads. But it seems likely that this is an 'as if' account, which he wants to bring in to explain 'efficient causes'. This is a useful point but it has given rise to the false claim that Leibniz believed in a 'psychophysical parallelism' which it is now agreed is a misreading at least in the sense that there is no duality of psycho and physical in his account. The best way to get to grips with this I would say is to read Dan Garber's 'Body, Substance, Monad' which is a brilliant analysis of the way Leibniz's mature metaphysic evolves. Garber covers all the possible interpretations and gives good reasons for his conclusions - and I think he has got it right. The Stanford Encyclopedia of Philosophy entries are also quite good on his abandonment of the mental/ physical dichotomy.

I have recently spent time on this because I think it helps understand perception int erms of modern physics. I have put my updated interpretation of Monadology on the web at http://www.ucl.ac.uk/jonathan-edwards/monadology.

It might be from a letter to de Volder, see the Google Books snippet below

http://books.google.co.th/books?id=fT7KAgAAQBAJ&pg=PA50&lpg=PA50&dq=wholes+have+only+a+borrowed+reality+leibniz&source=bl&ots=hDAJetyHiA&sig=640_hmhILNU7eMv9eosqFK6XEHg&hl=en&sa=X&ei=nykpU63QD8KkrQfJu4GQAQ&ved=0CDsQ6AEwAw#v=onepage&q=wholes%20have%20only%20a%20borrowed%20reality%20leibniz&f=false

Thank you Michael. Are you a Leibniz scholar?

From reading the reference you gave me Michael, I am not sure whether Leibniz is supporting this statement or whether he is saying this is de Volder's position and he is standing against this. What do you think?

@Paul, no, I'm not a Leibniz scholar. I've heard some lectures about Western philosophy during my physics studies (way before the Bologna process impeded such extravagant behaviour), so I remember Leibniz's idea of monadology.

Regarding his position in the text cited I'd say the first half of the paragraph are his own words because in the middle he says "But you [de Volder] ...hold that...". For serious referencing you will have to study the original text anyway, am I right?

Thanks for your answer Michael. Like you I am not a philosopher (I'm a psychologist and artist) but have had classes ages back.

You are correct, I will have to read the original but I appreciate your thoughts.

Dear Paul,

I am not a professional Leibniz scholar either but studying Leibniz is what I do much of the time and I shall be talking on the relation of Leibniz's metaphysics to modern physics at the Tercentenary Conference on the Monadology in Edinburgh in May. I think Michael's quote may well be the source for this. Leibniz says similar things many times in many manuscripts so it may be elsewhere as well.

One caution I would make is in the term 'whole'. What Leibniz is saying here, and it is his view, but maybe phrased in a way intended to be easy for a correspondent to understand, is that 'things' or objects or 'bodies' do not really exist as entities but are merely appearances of aggregates (of monadic entities). Some bodies, such as animals, (but he thinks probably not ceramic tiles) do have associated real entities which are their dominant monads but monads are entirely dynamic relational entities and do not themselves appear (individually) as 'matter'. So a cat as an object is merely an appearance of many component monadic elements but a cat also has a dominant dynamic spirit or soul which determines its actions but is invisible.

The point here is that the thing is not really a 'whole' - only as an idea in our head is it an entity. As a material body it is merely an appearance arising from an aggregate of units that may be thought of as parts of this **purely notional** quasi-entity. The relevance of this is that Leibniz denies that any real entity can have **any parts** because all real entities are indivisible and monadic. So it seems that Leibniz is using 'parts' here to help the reader but he is not wanting us to think that these are parts of a real 'whole'.

I apologise if that is a bit tortuous but this particular aspect of Leibniz's metaphysics causes a lot of confusion. Part of the problem is that up until about 1695 he recognised 'corporeal substances' in the sense of material entities. But by the Monadology of 1714 he had, it seems, decided that the only real entities existing in their own right (substances as they were called) were non-material dynamic monads. So in a sense by this stage he no longer recognises what a lot of people would call 'physical things'. Everything is purely dynamic and ideational. Unfortunately, towards the end of Monadology he makes it sound as if there still are bodies 'progressing in harmony' with individual monads. But it seems likely that this is an 'as if' account, which he wants to bring in to explain 'efficient causes'. This is a useful point but it has given rise to the false claim that Leibniz believed in a 'psychophysical parallelism' which it is now agreed is a misreading at least in the sense that there is no duality of psycho and physical in his account. The best way to get to grips with this I would say is to read Dan Garber's 'Body, Substance, Monad' which is a brilliant analysis of the way Leibniz's mature metaphysic evolves. Garber covers all the possible interpretations and gives good reasons for his conclusions - and I think he has got it right. The Stanford Encyclopedia of Philosophy entries are also quite good on his abandonment of the mental/ physical dichotomy.

I have recently spent time on this because I think it helps understand perception int erms of modern physics. I have put my updated interpretation of Monadology on the web at http://www.ucl.ac.uk/jonathan-edwards/monadology.

I'm not sure where exactly the line you refer to appears, as I'm not very familiar with translations of Leibniz outside lines translated in secondary text. However, Russell does provide a translation of one of Leibniz' letters to de Volder which is one of several that touches on this: "A thing which can be divided into several (already actually existing) is an aggregate of several, and...is not one except mentally, and has no reality but what is borrowed from its constituents. Hence I inferred that there must be in things indivisible unities, because otherwise there will be in things no true unity, and no reality not borrowed. Which is absurd. For where there is no true unity, there is no true multiplicity. And where there is no reality not borrowed, there will never be any reality, since this must in the end belong to some subject." (Russell, B. (1937). The Philosophy of Leibniz). The Latin reads "Quae res in plura (actu iam existentia) dividi potest, ex pluribus est aggregata, et res quae ex pluribus aggregata est, non est unum nisi mente nec habet realitatem nisi a contentis mutuatam. Hinc iam inferebam, ergo dantur in rebus unitates indivisibiles, quia alioqui nulla erit in rebus unitas vera, nec realitas non mutata. Quod est absurdum. Nam ubi nulla vera unitas, ibi nulla vera multitudo. Et ubi nulla est realitas nisi mutuata, nulla erit unquam realitas, cum ea debeat esse alicui tandem subjecto propria." (I've included the portion Russell replaces with ellipses, "res quae ex pluribus aggregate est", which may be rendered "a thing that is an aggregate of many [things]"). This issue, and the ways in which it was an issue de Volder had with Leibniz' view, are covered in somewhat greater detailed in Leibniz' previous letter (also from 1704, but from January not June).

Andrew and Jonathan, great answers (also for some brushing up of my long forgotten Latin).

I agree, this was a lesson in forgotten Latin from many years ago.