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Tag Archives: a priori

Butler and Clarke on the infinity of God

Juan Gomez writes…

In my three previous posts I have been commenting on the experimental methodology in religion and the contrast between the preferred methods of Samuel Clarke and Joseph Butler. We saw bishop Halifax’s general description of the a priori and a posteriori methods, and then we examined Butler’s preference for the latter and Clarke’s adoption of the former. Today I want to conclude this series of posts on religion by focusing on one specific application of the a priori method and Butler’s criticism of it.

In his A Demonstration of the being and attributes of God (1704) Clarke provides an argument for the infinity of God. As we have already mentioned in previous posts, Clarke prefers the a priori method because it provides ‘demonstrable proof’ of the attributes of God, while the a posteriori method can only provide probable knowledge. Clarke appeals to a set of premises from which he concludes that God, i.e. the only self-existing being, must be infinite. The following is Jonathan Bennett’s rephrasing of Clarke’s argument:

    ‘x is self-existent’ means that it’s a contradiction to suppose that x doesn’t exist
    ‘x is finite’ implies that there are places at which x doesn’t exist.


    It is a flat-out contradiction to suppose that something is both self-existent and finite.

So if you accept that God is self-existent, then you must also accept that he possesses the attribute of infinity. However, Butler is not convinced by this argument. In particular, Butler thinks that Clarke cannot say that if a being can be absent, without contradiction, from one place, then it can also be absent, without contradiction, from all places, which is exactly what Clarke claims is absurd. This is the passage that Butler criticises:

    “To suppose a Finite Being, to be Self-Existent; is to say that it is a Contradiction for that Being not to exist, the Absence of which may yet be conceived without a Contradiction: which is the greatest Absurdity in the  World: For if a Being can without Contradiction be absent from one place, it may without a Contradiction be absent likewise from another Place, and from all Places…”

Butler points out that a being, without contradiction can be absent from another and all places as long as it is at different times, but it is most certainly an absurdity to claim that a finite being can be absent from all places at the same time, since this would entail that it ceases to exist. Clarke replies that Butler is mistaken here, since it is indeed possible for a finite being to be absent of all places and all times, since such being is not necessary. Clarke appropriately switches back the conversation to talk of necessary beings, but this still is not enough to satisfy Butler.

In a follow up letter to Clarke’s reply, Butler now objects to the definition of self-existence. Butler argues that from the claim that a being necessarily exists it does not follow that it exists everywhere; it only follows that such being must exist somewhere, but there is no contradiction in supposing it is absent from other places at the same time.

It seems that the key to the whole discussion is the idea of necessity. If the self-existent being is necessary, then this must be the case everywhere, so it would be a contradiction to think that a necessary being is absent at one place. Butler seems to be missing this point in his exchange with Clarke. However, to be fair to Butler, at the time the correspondence took place, Butler was still very young (21 years old), and he eventually changed his mind and accepted Clarke’s argument.

However interesting the discussion between Butler and Clarke, I only wanted to provide an example of the way the debate between a priori and a posteriori methods took place within a religious context. Butler might have eventually accepted Clarke’s argument for the infinity of God, but 20 years after his correspondence with Clarke he was going to prefer the a posteriori method in his Analogy (1736), holding on to his belief that in matters of faith probable knowledge is all we need.

Why did Butler end up preferring the a posteriori method even though he accepted Clarke’s argument? The answer lies in the limits of knowledge that resulted from a commitment to experimental philosophy. Figures like Butler and Turnbull applied the experimental method to subjects that went beyond the observation of the natural world. This meant that the application of the experimental method could not be as straightforward as it was in natural philosophy, for the objects under consideration (‘moral objects’) are unobservable in the sense that they cannot be experienced via the five external senses. Knowledge of the existence of a future state and the attributes of God is not directly accessible to us, given our human nature. Anything we can possibly now about such things must be by analogy to the knowledge we gain from the observation of the natural world. This is why our knowledge of these ‘moral objects’ can never be demonstrable, but only probable. From our observation of the natural world we can safely conclude that it is probable that there is a future state, and highly probable that God is infinite (omnipresent), but we can never construct a demonstrable proof of these conclusions.

In one of the final exchanges on this topic Butler confesses that he insisted on his objection because he wanted a demonstrable proof of the infinity of God, and this misled him:

    “…your argument for the omnipresence of God seemed always to me very probable. But being very desirous to have it appear demonstrably conclusive, I was sometimes forced to say what was not altogether my opinion.”

Clarke suggests in his reply that this is a fault many are mislead into, and he blames one of the preferred targets of advocates of experimental philosophy, René Descartes:

    “…the universal prevalency of Cartes’s absurd notions (teaching that matter is necessarily infinite and necessarily eternal, and ascribing all things to mere mechanic laws of motion, exclusive of final causes, and of all will and intelligence and divine Providence from the government of the world) hath incredibly blinded the eyes of common reason, and prevented men from discerning him in whom they live and move and have their being…”

The upshot of applying the experimental method to moral topics was that it could only provide probable (not demonstrable) knowledge. However, recognizing this limitation was far more reasonable than those chimeras constructed by speculative philosophers.

Defining Early Modern Experimental Philosophy (2)

Alberto Vanzo writes…

In my last post, I raised the question as to whether there is any methodological view that was shared by all or most early modern experimental philosophers. To paraphrase Bas Van Fraassen, is there any statement E+ such that

    To endorse the method of (early modern) experimental philosophy = to believe that E+ (the experimentalists’ methodical dogma)?

As those of you who have followed this blog for a while will know, early modern experimental natural philosophers claimed that we should reject hypotheses and speculations (that is, roughly, natural-philosophical claims and theories) and rely instead on experiments and observations. In this post, I will discuss whether this claim, suitably understood, is the experimentalists’ methodical dogma. What does their rejection of hypotheses amount to?

The statement that we should reject hypotheses does not mean that we should avoid learning natural-philosophical claims and theories. On the contrary, according to Robert Hooke, learning hypotheses is beneficial because it helps us to devise new explanations and raise questions:

    the Mind will be somewhat more ready at guessing at the Solution of many Phenomena almost at first Sight, and thereby be much more prompt at making Queries, and at tracing the Subtilty of Nature, and in discovering and searching into the true Reason of things […]

Experimental philosophers also allow us to entertain claims and theories for the sake of testing them. Robert Boyle states in a letter to Oldenburg that natural histories should include “Circumstances” such that their “tryal or Observation” is “necessary or sufficient to prove or to invalidate this or that particular Hypothesis or Conjecture”.

Boyle’s statement makes clear that he allows for the acceptance of a natural-philosophical claims that are proven by “tryal [experiment] or Observation”. The claims in question must be those that are expressed by substantive or – in Kantian terms – synthetic a posteriori statements. Experiments and observations cannot prove analytic a priori statements. These are hardly the kind of statements that concerned experimental philosophers. Assuming that the analytic/synthetic distinction is tenable, accepting analytic a priori statements as true seems to be a harmless move anyway.

In the light of this, we may be tempted to paraphrase the rejection of hypotheses as follows:

    [A] Only commit to those substantive (as opposed to analytic) claims and theories that are warranted by experiments or observations.

[A] is in line with experimental philosophers’ rejection of arguments from authority, epitomized by the motto of the Royal Society: “nullius in verba“, which can be loosely translated as “take no man’s word for it”. [A] entails the rejection not only of arguments from authority, but also any kind of a priori arguments for substantive natural-philosophical claims – for instance, the arguments that Descartes used in the Principles of Philosophy to establish that material objects are made up of corpuscles. [A] has the welcome effect of classifying Descartes where, in my view, he belongs: outside of the movement of experimental philosophy, even though he too gathered natural-philosophical observations and performed some experiments.

However, [A] is inconsistent with the fact that many experimental philosophers were committed to substantive claims, like the corpuscularian and mechanist hypotheses, that were hardly warranted by the then extant empirical evidence. Boyle or Montanari did not seem to be concerned to provide detailed empirical arguments for corpuscularism or mechanism. However, they did not regard their acceptance of these views as being inconsistent with their commitment to experimentalism.

In view of this, I suggest replacing [A] with [B]:

    [B] Only firmly commit to those substantive claims and theories that are warranted by experiments and observations

and claiming that experimental philosophers like Boyle and Montanari did not firmly commit to corpuscularism and mechanism. They only weakly, tentatively, provisionally commit to these views, even though they were confident that future discoveries would dispel any doubt on their truth.

Is it correct to say that experimental philosophers’ commitments to mechanism and corpuscularism was typically weak, provisional, tentative? Are there other claims on the natural world that experimental philosophers firmly endorsed, even though the then available empirical evidence did not warrant them? Can a clear distinction between weak, provisional, tentative and strong, definitive, firm commitments be drawn, and if so, how? If you have any suggestions on how these questions should be answered, please let me know in the comments or get in touch. Answering these questions is important to establish if my suggestion that [B] represents a suitable candidate for the experimentalists’ methodical dogma is persuasive.

Samuel Clarke on arguing a priori

Juan Gomez writes…

In my two previous posts I explored Butler’s preferred methodology in the Analogy and the Sermons. We first looked at bishop Halifax’s description of Butler’s work and then we reviewed the latter’s own methodological statements. Both Butler and Halifax describe two methods used in arguing for the existence and attributes of God: a posteriori and a priori. They identify the latter of these methods with the work of Samuel Clarke. Since we have already discussed at some length Butler’s methodology, I want to spend this post analysing the comments Clarke (one of the leading Newtonians of the first decades of the eighteenth century) makes regarding his use of the a priori method.

Clarke was sympathetic to the experimental method as practised by Newton and he was especially interested in the application of mathematics to metaphysics, which is the project carried out in his Boyle lectures, A Demonstration of the being and attributes of God (1704) and A discourse concerning the unchangeable obligations of natural religion (1705). In the text of the lectures themselves there is not much regarding methodology, other than Clarke stating that his method is “as near to Mathematical as the nature of such a Discourse would allow.” However, subsequent editions of the discourse included Clarke’s replies to objections where in his answers to the sixth and seventh letters he explains in more detail his use of the a priori method. In the former he briefly explains why he prefers it by contrasting it with the a posteriori method:

    The Proof a posteriori is level to All Mens Capacities: Because there is an endless gradation of wise and useful phænomena of Nature, from the most obvious to the most abstruse; which afford (at least moral and reasonable) Proof of the Being of God, to the several Capacities of All unprejudiced Men… The Proof a priori, is (I fully believe) strictly demonstrative; but (like numberless Mathematical Demonstrations,) capable of being understood by only a few attentive Minds; because ’tis of Use, only against Learned and Metaphysical Difficulties

So on one hand the a posteriori proof is accessible to more people, but it provides only reasonable (not demonstrable) proof; on the other, the a priori way of arguing provides demonstrative proof, but it is only reserved for a few minds engaged in metaphysical disputations. Clarke prefers the a priori method in this case (i.e. in natural theology) because it can provide him with demonstrative proof of the attributes of God. However, this method is not meant to be in direct opposition to the a posteriori method, but rather complement it. This is what Clarke mentions in his preface to the Discourse:

    The Honourable Robert Boyle, Esq; was a Person no less zealously solicitous for the propagation of true Religion, and the practice of Piety and Virtue; than diligent and successful in improving Experimental Philosophy, and in inlarging our Knowledge of Nature. And it was his settled Opinion, that the advancement and increase of Natural Knowledge, would always be of Service to the Cause and Interest of true Religion, in opposition to Atheists and Unbelievers of all sorts… In pursuance of which End I endeavoured, in my former Discourse [the Demonstration], to strengthen and confirm the Arguments which prove to us the Being and Attributes of God, partly by metaphysical Reasoning, and partly from the Discoveries (principally those that have been late made) in Natural Philosophy.

Clarke believes that both ways of arguing complement each other and both prove the attributes of God. In his Answer to the Seventh Letter Clarke justifies in more detail his use of the a priori method. Clarke believes that an a priori argument is necessary to carry further what the a posteriori argument proves. He recognizes that the latter “ought always to be distinctly insisted upon,” but the a priori argument is useful to answer objections against the attributes of God at a metaphysical level. Further, Clarke explains that the a posteriori argument by itself cannot prove the eternity, infinity and unity of God:

    The Temporary phænomena of nature, prove indeed demonstrably a posteriori, that there is, and has been from the beginning of those phænomena, a Being of Power and Wisdom sufficient to produce and preserve those phænomena. But that This First Cause has existed from Eternity, and shall exist to Eternity, cannot be proved from those Temporary phænomena; but must be demonstrated from the intrinsick Nature of Necessary-Existence.

In a similar vein, Clarke comments that from the observation of the phænomena of nature we can only prove that there is a Being with sufficient power and wisdom, but not that such being is absolutely infinite and universal. What I want to point out here is that the two methods in consideration should be interpreted as complementary and not as opposed to each other. However, Clarke’s a priori arguments regarding the attributes of God were widely criticized, even from those who shared his Newtonianism and admired the mathematical method that Newton successfully applied in his natural philosophy. One of these critics is Joseph Butler, and in my next post I will examine the discussion between this two figures regarding the attribute of infinity.

Leibniz: An Experimental Philosopher?

Alberto Vanzo writes…

In an essay that he published anonymously, Newton used the distinction between experimental and speculative philosophy to attack Leibniz. Newton wrote: “The Philosophy which Mr. Newton in his Principles and Optiques has pursued is Experimental.” Newton went on claiming that Leibniz, instead, “is taken up with Hypotheses, and propounds them, not to be examined by experiments, but to be believed without Examination.”

Leibniz did not accept being classed as a speculative armchair philosopher. He retorted: “I am strongly in favour of the experimental philosophy, but M. Newton is departing very far from it”.

In this post, I will discuss what Leibniz’s professed sympathy for experimental philosophy amounts to. Was Newton right in depicting him as a foe of experimental philosophy?

To answer this question, let us consider four typical features of early modern experimental philosophers:

  1. self-descriptions: experimental philosophers typically called themselves such. At the very least, they professed their sympathy towards experimental philosophy.
  2. friends and foes: experimental philosophers saw themselves as part of a tradition whose “patriarch” was Bacon and whose sworn enemy was Cartesian natural philosophy.
  3. method:experimental philosophers put forward a two-stage model of natural philosophical inquiry: first, collect data by means of experiments and observations; second, build theories on the basis of them. In general, experimental philosophers emphasized the a posteriori origins of our knowledge of nature and they were wary of a priori reasonings.
  4. rhetoric: in the jargon of experimental philosophers, the terms “experiments” and “observations” are good, “hypotheses” and “speculations” are bad. They were often described as fictions, romances, or castles in the air.
  5. Did Leibniz have the four typical features of experimental philosophers?

    First, he declared his sympathy for experimental philosophy in passage quoted at the beginning of this post.

    Second, Leibniz had the same friends and foes of experimental philosophers. He praised Bacon for ably introducing “the art of experimenting”. Speaking of Robert Boyle’s air pump experiments, he called him “the highest of men”. He also criticized Descartes in the same terms as British philosophers:

      if Descartes had relied less on his imaginary hypotheses and had been more attached to experience, I believe that his physics would have been worth following […] (Letter to C. Philipp, 1679)

    Third, the natural-philosophical method of the mature Leibniz displays many affinities with the method of experimental philosophers. To know nature, a “catalogue of experiments is to be compiled” [source]. We must write Baconian natural histories. Then we should “infer a maximum from experience before giving ourselves a freer way to hypotheses” (letter to P.A. Michelotti, 1715). This sounds like the two-stage method that experimental philosophers advocated: first, collect data; second, theorize on the basis of the data.

    Fourth, Leibniz embraces the rhetoric of experimental philosophers, but only in part. He places great importance on experiments and observations. However, he does not criticize hypotheses, speculations, or demonstrative reasonings from first principles as such. This is because demonstrative, a priori reasonings play an important role in Leibniz’s natural philosophy.

    Leibniz thinks that we can prove some general truths about the natural world a priori: for instance, the non-existence of atoms and the law of equality of cause and effect. More importantly, a priori reasonings are necessary to justify our inductive practices.

    When experimental natural philosophers make inductions, they presuppose the truth of certain principles, like the principle of the uniformity of nature: “if the cause is the same or similar in all cases, the effect will be the same or similar in all”. Why should we take this and similar principles to be true? Leibniz notes:

      [I]f these helping propositions, too, were derived from induction, they would need new helping propositions, and so on to infinity, and moral certainty would never be attained. [source]

    There is the danger of an infinite regress. Leibniz avoided it by claiming that the assumption of the uniformity of nature is warranted by a priori arguments. These prove that the world God created obeys to simple and uniform natural laws.

    In conclusion, Leibniz really was, as he wrote, “strongly in favour of the experimental philosophy”. However, he aimed to combine it with a set of a priori, speculative reasonings. These enable us to prove some truths on the constitution of the natural world and justify our inductive practices. Leibniz’s reflections are best seen not as examples of experimental or speculative natural philosophy, but as eclectic attempts to combine the best features of both approaches. In his own words, Leibniz intended “to unite in a happy wedding theoreticians and observers so as to improve on incomplete and particular elements of knowledge” (Grundriss eines Bedenckens […], 1669-1670).