Combining Texts

All the ideas for 'reports', 'De Corpore (Elements, First Section)' and 'Aristotle and Descartes on Matter'

unexpand these ideas     |    start again     |     specify just one area for these texts


58 ideas

1. Philosophy / D. Nature of Philosophy / 1. Philosophy
He studied philosophy by suspending his judgement on everything [Pyrrho, by Diog. Laertius]
     Full Idea: He studied philosophy on the principle of suspending his judgement on all points.
     From: report of Pyrrho (reports [c.325 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 09.Py.3
     A reaction: In what sense was Pyrrho a philosopher, then? He must have asserted SOME generalised judgments.
1. Philosophy / D. Nature of Philosophy / 5. Aims of Philosophy / e. Philosophy as reason
Definitions are the first step in philosophy [Hobbes]
     Full Idea: In beginning philosophy, the first beginning is from definitions.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 1.6.15)
     A reaction: Note that he doesn't say that definitions are the aim of philosophy, as some analysts might think.
2. Reason / A. Nature of Reason / 9. Limits of Reason
Sceptics say reason is only an instrument, because reason can only be attacked with reason [Pyrrho, by Diog. Laertius]
     Full Idea: The Sceptics say that they only employ reason as an instrument, because it is impossible to overturn the authority of reason, without employing reason.
     From: report of Pyrrho (reports [c.325 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 09.Py.8
2. Reason / D. Definition / 2. Aims of Definition
Definitions of things that are caused must express their manner of generation [Hobbes]
     Full Idea: Definitions of things which may be understood to have some cause, must consist of such names as express the cause or manner of their generation, as when we define a circle to be a figure made by the circumduction of a straight line in a plane etc.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 1.6.13)
     A reaction: His account of the circle is based on its mode of construction, which is the preferred account of Euclid, rather than a statement of its pure nature.
2. Reason / D. Definition / 5. Genus and Differentia
Definition is resolution of names into successive genera, and finally the difference [Hobbes]
     Full Idea: The definition is nothing but a resolution of the name into its most universal parts; ...definitions of this kind always consist of genus and difference; the former names being all, till the last, general; and the last of all, difference.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 1.6.14)
     A reaction: This is basically the scholastic Aristotelian view of definition. Note that Hobbes explicitly denies that the last step of the definition is general in character.
2. Reason / D. Definition / 8. Impredicative Definition
A defined name should not appear in the definition [Hobbes]
     Full Idea: A defined name ought not to be repeated in the definition. ...No total can be part of itself.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 1.6.15)
2. Reason / F. Fallacies / 3. Question Begging
'Petitio principii' is reusing the idea to be defined, in disguised words [Hobbes]
     Full Idea: 'Petitio principii' is when the conclusion to be proved is disguised in other words, and put for the definition or principle from whence it is to be demonstrated.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 1.6.18)
4. Formal Logic / G. Formal Mereology / 3. Axioms of Mereology
A part of a part is a part of a whole [Hobbes]
     Full Idea: A part of a part is a part of a whole.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 2.07.09)
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / e. Ordinal numbers
If we just say one, one, one, one, we don't know where we have got to [Hobbes]
     Full Idea: By saying one, one, one, one, and so forward, we know not what number we are at beyond two or three.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 2.12.05)
     A reaction: This makes ordinals sound like meta-numbers.
7. Existence / B. Change in Existence / 1. Nature of Change
Change is nothing but movement [Hobbes]
     Full Idea: All mutation consists in motion only
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 2.09.06)
     A reaction: Another little gem of simplicity from Hobbes, and one with which I am inclined to agree. The value of a variable can 'change', but that may be metaphorical.
8. Modes of Existence / B. Properties / 8. Properties as Modes
Accidents are just modes of thinking about bodies [Hobbes]
     Full Idea: An accident is a mode of conceiving a body.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 2.08.02)
     A reaction: In contrast to the other thinkers who followed Suárez on modes in the early 17th century, Hobbes thinks they are just ways of 'conceiving' bodies, rather than actual features of them.
8. Modes of Existence / B. Properties / 12. Denial of Properties
Accidents are not parts of bodies (like blood in a cloth); they have accidents as things have a size [Hobbes]
     Full Idea: An accident's being in a body is not to be taken as something contained in that body - as if redness were in blood like blood in a bloody cloth, as part of the whole, for then accident would be a body. It is like body having size or rest or movement.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 2.08.03)
     A reaction: [compressed] Hobbes is fishing for something like the Quinean view of properties, but no one seems to be able to articulate this sceptical view very well. Pasnau says he means to talk of 'the mode of conceiving a body' (De C 8.2).
8. Modes of Existence / C. Powers and Dispositions / 3. Powers as Derived
The complete power of an event is just the aggregate of the qualities that produced it [Hobbes]
     Full Idea: The power of agent and patient taken together, which may be called the complete power, is the same as the complete cause, for each consists in the aggregation together of all the accidents that are required to produce an effect in both agent and patient.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 2.10.01)
     A reaction: They treat powers as macro phenomena, and don't seem to have a sense of the basic powers that build up the big picture.
8. Modes of Existence / E. Nominalism / 1. Nominalism / b. Nominalism about universals
The only generalities or universals are names or signs [Hobbes]
     Full Idea: Nothing is general or universal besides names or signs.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 2.08.05)
     A reaction: This is the perfect motto for nominalists, among which I am inclined to include myself. Hobbes had a fabulous gift for economy of phrasing. This website is dedicated to that ideal. Reality does not contain generalities (obviously!!).
9. Objects / A. Existence of Objects / 5. Individuation / c. Individuation by location
Bodies are independent of thought, and coincide with part of space [Hobbes]
     Full Idea: A body is that, which having no dependence on our thought, is coincident or coextended with some part of space.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 2.08.01)
     A reaction: This rather Cartesian view doesn't seem to offer any distinction between empty space and space containing an 'object'. Presumably it is the ancestor of the Quinean account just in terms of space-time points. Don't like it.
If you separate the two places of one thing, you will also separate the thing [Hobbes]
     Full Idea: One body cannot be in two places at the same time, ...for the place that a body fills being divided into two, the placed body will also be divided into two; the place and the body that fills that place are divided both together.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 2.08.08)
     A reaction: If every time you manipulated one body it affected both of them, you might say that one body was in two places, rather like a mirror image.
If you separated two things in the same place, you would also separate the places [Hobbes]
     Full Idea: Two bodies cannot be together in the same place, ..because when a body that fills its whole place is divided into two, the place itself is divided into two also, so that there will be two places.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 2.08.08)
     A reaction: The wonderful things about philosophy is that you are faced with obvious truths of the world, and cannot begin to think why they are true - and then up steps a philosopher and offers you a reason.
9. Objects / B. Unity of Objects / 1. Unifying an Object / b. Unifying aggregates
If a whole body is moved, its parts must move with it [Hobbes]
     Full Idea: How can any whole body be moved, unless all its parts be moved together with it?
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 2.08.05)
     A reaction: This might be a distinguishing mark for a whole physical body. I think it is probably the main mark for ordinary folk. I've never found this idea in Aristotle.
9. Objects / C. Structure of Objects / 8. Parts of Objects / b. Sums of parts
A body is always the same, whether the parts are together or dispersed [Hobbes]
     Full Idea: A body is always the same, whether the parts of it be put together or dispersed; or whether it be congealed or dissolved.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 2.11.07)
     A reaction: This appears to be a commitment by Hobbes to what we now call 'classical' mereology - that any bunch of things can count as a whole, whether they are together or dispersed. He seems to mean more than a watch surviving dismantling.
9. Objects / C. Structure of Objects / 8. Parts of Objects / c. Wholes from parts
To make a whole, parts needn't be put together, but can be united in the mind [Hobbes]
     Full Idea: In composition, it is to be understood that for the making up of a whole there is no need of putting the parts together, so as to make them touch one another, but only of collecting them into one sum in the mind.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 2.07.08)
     A reaction: This seems to the 'unrestricted composition' of classical mereology, since it appears that Hobbes offers no restriction on which parts can be united by a mind, no matter how bizarre.
9. Objects / D. Essence of Objects / 5. Essence as Kind
Particulars contain universal things [Hobbes]
     Full Idea: Universal things are contained in the nature of singular things.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 1.6.04)
     A reaction: That is the neatest and most accurate summary of the situation I have ever read. Particulars come first, but they are all riddled with generalities (but that is not as well said as Hobbes's remark).
9. Objects / D. Essence of Objects / 7. Essence and Necessity / b. Essence not necessities
Some accidental features are permanent, unless the object perishes [Hobbes]
     Full Idea: There are certain accidents which can never perish except the body perish also.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 2.08.03)
     A reaction: He is just making an observation, and not proposing a theory about essence.
9. Objects / D. Essence of Objects / 13. Nominal Essence
The feature which picks out or names a thing is usually called its 'essence' [Hobbes]
     Full Idea: That accident for which we give a certain name to any body, or the accident which denominates its subject, is commonly called the essence thereof.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 2.08.23)
     A reaction: This is clearly a prelude to Locke's more carefully formulated 'nominal essence'. Fairly obvious, for nominalist empiricists. A bit surprising to say this was 'common'.
9. Objects / E. Objects over Time / 8. Continuity of Rivers
It is the same river if it has the same source, no matter what flows in it [Hobbes]
     Full Idea: That will be the same river which flows from one and the same fountain, whether the same water, or other water, or something other than water, flow thence.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 2.11.07)
     A reaction: This makes the source the one necessity for a river. I think the end matters too. If the Thames reversed direction, and flowed into Wales, it would not be the Thames any more.
9. Objects / E. Objects over Time / 9. Ship of Theseus
Some individuate the ship by unity of matter, and others by unity of form [Hobbes]
     Full Idea: In the Ship of Theseus, some place individuity in the unity of matter; others, in the unity of form.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 2.11.07)
     A reaction: Simons raises this comment into a dogma, that there are at least two objects present in the ship. If I offered you a sum for the contents of your house, they would have a unity of monetary value.
If a new ship were made of the discarded planks, would two ships be numerically the same? [Hobbes]
     Full Idea: If some man kept the old planks as they were taken out, and by putting them afterwards together again in the same order, had again made a ship of them, ...there would have been two ships numerically the same, which is absurd.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 2.11.07)
     A reaction: This is the origin of the famous modern problematical example of the Ship of Theseus. The ancient example is just the case of whether you step into the same river, but using an artefact with parts, to make it clearer.
9. Objects / F. Identity among Objects / 3. Relative Identity
As an infant, Socrates was not the same body, but he was the same human being [Hobbes]
     Full Idea: It makes a great difference to ask concerning Socrates whether he is the same human being or whether he is the same body. For his body, when he is old, cannot be the same it was when he was an infant. …He can, however, be the same human being.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 2.11.07)
     A reaction: This is not commitment to full (Geachian) relative identity, but it notes the problem.
9. Objects / F. Identity among Objects / 8. Leibniz's Law
Two bodies differ when (at some time) you can say something of one you can't say of the other [Hobbes]
     Full Idea: Two bodies are said to differ from one another, when something may be said of one of them, which cannot be said of the other at the same time.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 2.11.02)
     A reaction: Note the astute addition of 'at the same time'. Note also that it is couched in terms of what is true, rather than in terms of 'properties' or 'accidents'.
10. Modality / D. Knowledge of Modality / 4. Conceivable as Possible / b. Conceivable but impossible
We can imagine a point swelling and contracting - but not how this could be done [Hobbes]
     Full Idea: Even if we can feign in our mind that a point swells to a huge bulk and then contracts to a point - imagining something's made from nothing (ex nihilo), and nothing's made from something - still we cannot comprehend how this could be done in nature.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 2.08.20)
     A reaction: [compressed] Pasnau notes that this offers two sorts of conceivability, of something happening, and of a reason for it happening. A really nice idea, significant (I think) for scientific essentialists, who say possibilities are fewer than you think.
13. Knowledge Criteria / A. Justification Problems / 1. Justification / a. Justification issues
If we need a criterion of truth, we need to know whether it is the correct criterion [Pyrrho, by Fogelin]
     Full Idea: Against the Stoics, the Pyrrhonians argued that if someone presents a criterion of truth, then it will be important to determine whether it is the correct criterion.
     From: report of Pyrrho (reports [c.325 BCE]) by Robert Fogelin - Walking the Tightrope of Reason Ch.4
     A reaction: Hence Davidson says that attempts to define truth are 'folly'. If something has to be taken as basic, then truth seems a good candidate (since, for example, logical operators could not otherwise be defined by means of 'truth' tables).
13. Knowledge Criteria / D. Scepticism / 1. Scepticism
The Pyrrhonians attacked the dogmas of professors, not ordinary people [Pyrrho, by Fogelin]
     Full Idea: The attacks of the Pyrrhonian sceptics are directed against the dogmas of the 'professors', not against the beliefs of the common people pursuing the business of daily life.
     From: report of Pyrrho (reports [c.325 BCE]) by Robert Fogelin - Walking the Tightrope of Reason Ch.4
     A reaction: This may be because they thought that ordinary people were too confused to be worth attacking, rather than because they lived in a state of beautifully appropriate beliefs. Naďve realism is certainly worth attacking.
13. Knowledge Criteria / D. Scepticism / 6. Scepticism Critique
Academics said that Pyrrhonians were guilty of 'negative dogmatism' [Pyrrho, by Fogelin]
     Full Idea: The ancient Academic sceptics charged the Pyrrhonian sceptics with 'negative dogmatism' when they claimed that a certain kind of knowledge is impossible.
     From: report of Pyrrho (reports [c.325 BCE]) by Robert Fogelin - Walking the Tightrope of Reason Ch.4
     A reaction: It is this kind of point which should push us towards some sort of rationalism, because certain a priori 'dogmas' seem to be indispensable to get any sort of discussion off the ground. The only safe person is Cratylus (see Idea 578).
13. Knowledge Criteria / E. Relativism / 1. Relativism
Judgements vary according to local culture and law (Mode 5) [Pyrrho, by Diog. Laertius]
     Full Idea: Fifth mode: judgements vary according to local custom, law and culture (Persians marry their daughters).
     From: report of Pyrrho (reports [c.325 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 09.Py.9
Objects vary according to which sense perceives them (Mode 3) [Pyrrho, by Diog. Laertius]
     Full Idea: Third mode: things like an apple vary according to which sense perceives them (yellow, sweet, and fragrant).
     From: report of Pyrrho (reports [c.325 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 09.Py.9
Perception varies with viewing distance and angle (Mode 7) [Pyrrho, by Diog. Laertius]
     Full Idea: Seventh mode: perception varies according to viewing distance and angle (the sun, and a dove's neck).
     From: report of Pyrrho (reports [c.325 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 09.Py.9
Perception and judgement depend on comparison (Mode 10) [Pyrrho, by Diog. Laertius]
     Full Idea: Tenth mode: perceptions and judgements depend on comparison (light/heavy, above/below).
     From: report of Pyrrho (reports [c.325 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 09.Py.9
Individuals vary in responses and feelings (Mode 2) [Pyrrho, by Diog. Laertius]
     Full Idea: Second mode: individual men vary in responses and feelings (heat and cold, for example).
     From: report of Pyrrho (reports [c.325 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 09.Py.9
Animals vary in their feelings and judgements (Mode 1) [Pyrrho, by Diog. Laertius]
     Full Idea: First mode: animals vary in their feelings and judgements (of food, for example).
     From: report of Pyrrho (reports [c.325 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 09.Py.9
Perception varies with madness or disease (Mode 4) [Pyrrho, by Diog. Laertius]
     Full Idea: Fourth mode: perceivers vary in their mental and physical state (such as the mad and the sick).
     From: report of Pyrrho (reports [c.325 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 09.Py.9
Perception of things depends on their size or quantity (Mode 8) [Pyrrho, by Diog. Laertius]
     Full Idea: Eighth mode: perceptions of things depend on their magnitude or quantity (food and wine).
     From: report of Pyrrho (reports [c.325 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 09.Py.9
Perception of objects depends on surrounding conditions (Mode 6) [Pyrrho, by Diog. Laertius]
     Full Idea: Sixth mode: the perception of an object depends on surrounding conditions (sunlight and lamplight).
     From: report of Pyrrho (reports [c.325 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 09.Py.9
Perception is affected by expectations (Mode 9) [Pyrrho, by Diog. Laertius]
     Full Idea: Ninth mode: we perceive things according to what we expect (earthquakes and sunshine).
     From: report of Pyrrho (reports [c.325 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 09.Py.9
14. Science / D. Explanation / 2. Types of Explanation / g. Causal explanations
Science aims to show causes and generation of things [Hobbes]
     Full Idea: The end of science is the demonstration of the causes and generation of things.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 1.6.13)
15. Nature of Minds / C. Capacities of Minds / 2. Imagination
Imagination is just weakened sensation [Hobbes]
     Full Idea: Imagination is nothing else but sense decaying or weakened by the absence of the object.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 4.25.07)
     A reaction: This sounds more like memory than imagination. He needs to say something about unusual combinations of memories, I would have thought.
15. Nature of Minds / C. Capacities of Minds / 10. Conatus/Striving
A 'conatus' is an initial motion, experienced by us as desire or aversion [Hobbes, by Arthur,R]
     Full Idea: Hobbes' notion of 'conatus' is a 'beginning of motion' - a motion through a point of space in an instant of time. In a human subject this is experience as desire or aversion. It thus forms a bridge between physics and psychology.
     From: report of Thomas Hobbes (De Corpore (Elements, First Section) [1655], p.178) by Richard T.W. Arthur - Leibniz 3 'Worlds'
     A reaction: This sounds rather like the primitive concept of a power which I like, but the term seems to be used very vaguely, and never discussed carefully. The idea provoked Leibniz to connect physical force with mental life.
17. Mind and Body / E. Mind as Physical / 1. Physical Mind
Sensation is merely internal motion of the sentient being [Hobbes]
     Full Idea: Sense in the sentient, can be nothing else but motion in some of the internal parts of the sentient; and the parts so moved are parts of the organs of sense.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 3.15.02)
     A reaction: Amazingly bold for the time, and presumably influenced by Lucretius. I am sympathetic, but to suggest that sensation is nothing more sounds a bit like a category mistake. Has he grasped that the brain is involved?
18. Thought / A. Modes of Thought / 3. Emotions / e. Basic emotions
Apart from pleasure and pain, the only emotions are appetite and aversion [Hobbes]
     Full Idea: All the passions, called passions of the mind, consist of appetite and aversion, except pure pleasure and pain.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 4.25.13)
     A reaction: He now faces the challenge of explaining all the many other emotions in terms of these two. Good luck with that, Thomas.
18. Thought / B. Mechanics of Thought / 5. Mental Files
Words are not for communication, but as marks for remembering what we have learned [Hobbes]
     Full Idea: The use of words consists in this, that they may serve for marks by which whatsoever we have found out may be recalled to memory ...but not as signs by which we declare the same to others.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 1.6.11)
     A reaction: This exactly fits the idea of mental files, of which I am a fan. That this is the actual purpose of language is an unusual but interesting view.
26. Natural Theory / A. Speculations on Nature / 6. Early Matter Theories / b. Prime matter
Prime matter is body considered with mere size and extension, and potential [Hobbes]
     Full Idea: Prime matter signifies body considered without the consideration of any form or accident except only magnitude or extension, and aptness to receive form and accidents.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 2.08.24)
     A reaction: I take 'considered without' to indicate that he thinks of it as a psychological abstraction, rather than some actual existing thing.
Prime matter is nothing when it is at rest [Leibniz]
     Full Idea: Primary matter is nothing if considered at rest.
     From: Gottfried Leibniz (Aristotle and Descartes on Matter [1671], p.90)
     A reaction: This goes with Leibniz's Idea 13393, that activity is the hallmark of existence. No one seems to have been able to make good sense of prime matter, and it plays little role in Aristotle's writings.
26. Natural Theory / C. Causation / 1. Causation
Acting on a body is either creating or destroying a property in it [Hobbes]
     Full Idea: A body is said to work upon or act, that is to say, do something to another body, when it either generates or destroys some accident in it.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 2.09.01)
26. Natural Theory / C. Causation / 7. Eliminating causation
There are no causes, because they are relative, and alike things can't cause one another [Pyrrho, by Diog. Laertius]
     Full Idea: The idea of cause is relative to that of which it is the cause, and so has no real existence. …Also cause must either be body causing body, or incorporeal causing incorporeal, and neither of these is possible.
     From: report of Pyrrho (reports [c.325 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 09.11.11
26. Natural Theory / C. Causation / 8. Particular Causation / c. Conditions of causation
An effect needs a sufficient and necessary cause [Hobbes]
     Full Idea: There can be no effect but from a sufficient and necessary cause.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 2.10.02)
     A reaction: To be compared with Mackie's subtler modern account of this matter. If two different separate causes could lead to the same result, it is hard to see how the cause must be 'necessary' (unless you say they lead to different effects).
26. Natural Theory / C. Causation / 9. General Causation / d. Causal necessity
A cause is the complete sum of the features which necessitate the effect [Hobbes]
     Full Idea: A cause it the sum or aggregate of all such accidents, both in the agents and in the patient, as concur to the producing of the effect propounded; all of which existing together, ti cannot be understood but that the effect existenth without them.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 1.6.10)
     A reaction: For most causes we meet, this definition will include gravity and electro-magnetism, so it doesn't help in narrowing things down. Notice that he accepts the necessity, despite his committed empiricism.
27. Natural Reality / A. Classical Physics / 1. Mechanics / a. Explaining movement
Motion can't move where it is, and can't move where it isn't, so it can't exist [Pyrrho, by Diog. Laertius]
     Full Idea: Motion is not moved in the place in which it is is, and it is impossible that it should be moved in the place in which it is not, so there is no such thing as motion.
     From: report of Pyrrho (reports [c.325 BCE]) by Diogenes Laertius - Lives of Eminent Philosophers 09.11.11
Motion is losing one place and acquiring another [Hobbes]
     Full Idea: Motion is privation of one place, and the acquisition of another.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 1.6.06)
     A reaction: This is basically the 'at-at' theory of motion which empiricists like, because it breaks motion down into atoms of experience. Hobbes needs an ontology which includes 'places'.
27. Natural Reality / A. Classical Physics / 1. Mechanics / c. Forces
'Force' is the quantity of movement imposed on something [Hobbes]
     Full Idea: I define 'force' to be the impetus or quickness of motion multiplied either into itself, or into the magnitude of the movent, by means of which whereof the said movent works more or less upon the body that resists it.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 3.15.02)
     A reaction: Not very helpful, perhaps, but it shows a view of force at quite an early date, well before Newton.
27. Natural Reality / D. Time / 2. Passage of Time / k. Temporal truths
Past times can't exist anywhere, apart from in our memories [Hobbes]
     Full Idea: When people speak of the times of their predecessors, they do not think after their predecessors are gone that their times can be any where else than in the memory of those that remember.
     From: Thomas Hobbes (De Corpore (Elements, First Section) [1655], 2.07.03)