Some prior knowledge of college-level mathematics and physics is presupposed, but otherwise the book is suitable for use in an advanced undergraduate or beginning graduate course in the philosophy of science. While writing I had in mind primarily a The title of this work is to be taken seriously: it is a small book for teaching students to read the language of determinism. While writing I had in mind primarily a philosophical audience, but I hope that students and colleagues from the sciences will also find the treatment of scientific issues of interest. Though modest in not trying to reach beyond an introductory level of analysis, the work is decidedly immodest in trying to change a number of misimpressions that pervade the philosophical literature. For example, when told that classical physics is not the place to look for clean and unproblematic examples of determinism, most philosophers react with a mixture of disbelief and incomprehension.
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Introduction In most of what follows, I will speak simply of determinism, rather than of causal determinism. This follows recent philosophical practice of sharply distinguishing views and theories of what causation is from any conclusions about the success or failure of determinism cf.
Earman, ; an exception is Mellor For the most part this disengagement of the two concepts is appropriate. Traditionally determinism has been given various, usually imprecise definitions. This is only problematic if one is investigating determinism in a specific, well-defined theoretical context; but it is important to avoid certain major errors of definition. In order to get started we can begin with a loose and nearly all-encompassing definition as follows: Determinism: The world is governed by or is under the sway of determinism if and only if, given a specified way things are at a time t, the way things go thereafter is fixed as a matter of natural law.
The italicized phrases are elements that require further explanation and investigation, in order for us to gain a clear understanding of the concept of determinism. The roots of the notion of determinism surely lie in a very common philosophical idea: the idea that everything can, in principle, be explained, or that everything that is, has a sufficient reason for being and being as it is, and not otherwise.
In other words, the roots of determinism lie in what Leibniz named the Principle of Sufficient Reason. But since precise physical theories began to be formulated with apparently deterministic character, the notion has become separable from these roots. Since the first clear articulations of the concept, there has been a tendency among philosophers to believe in the truth of some sort of determinist doctrine. There has also been a tendency, however, to confuse determinism proper with two related notions: predictability and fate.
Fatalism is the thesis that all events or in some versions, at least some events are destined to occur no matter what we do. The source of the guarantee that those events will happen is located in the will of the gods, or their divine foreknowledge, or some intrinsic teleological aspect of the universe, rather than in the unfolding of events under the sway of natural laws or cause-effect relations.
Not every metaphysical picture makes this disentanglement possible, of course. In a looser sense, however, it is true that under the assumption of determinism, one might say that given the way things have gone in the past, all future events that will in fact happen are already destined to occur. Prediction and determinism are also easy to disentangle, barring certain strong theological commitments.
As the following famous expression of determinism by Laplace shows, however, the two are also easy to commingle: We ought to regard the present state of the universe as the effect of its antecedent state and as the cause of the state that is to follow.
An intelligence knowing all the forces acting in nature at a given instant, as well as the momentary positions of all things in the universe, would be able to comprehend in one single formula the motions of the largest bodies as well as the lightest atoms in the world, provided that its intellect were sufficiently powerful to subject all data to analysis; to it nothing would be uncertain, the future as well as the past would be present to its eyes.
The perfection that the human mind has been able to give to astronomy affords but a feeble outline of such an intelligence. Laplace In this century, Karl Popper defined determinism in terms of predictability also, in his book The Open Universe. Laplace probably had God in mind as the powerful intelligence to whose gaze the whole future is open.
If not, he should have: 19th and 20th century mathematical studies showed convincingly that neither a finite, nor an infinite but embedded-in-the-world intelligence can have the computing power necessary to predict the actual future, in any world remotely like ours. But even if our aim is only to predict a well-defined subsystem of the world, for a limited period of time, this may be impossible for any reasonable finite agent embedded in the world, as many studies of chaos sensitive dependence on initial conditions show.
Conversely, certain parts of the world could be highly predictable, in some senses, without the world being deterministic. When it comes to predictability of future events by humans or other finite agents in the world, then, predictability and determinism are simply not logically connected at all. Were she then to watch me live through it, she might smile condescendingly, as one who watches a marionette dance to the tugs of strings that it knows nothing about.
Nor does it matter whether any demon or even God can, or cares to, actually predict what we will do: the existence of the strings of physical necessity, linked to far-past states of the world and determining our current every move, is what alarms us. Whether such alarm is actually warranted is a question well outside the scope of this article see Hoefer a , Ismael and the entries on free will and incompatibilist theories of freedom.
But a clear understanding of what determinism is, and how we might be able to decide its truth or falsity, is surely a useful starting point for any attempt to grapple with this issue. We return to the issue of freedom in section 6, Determinism and Human Action , below. Conceptual Issues in Determinism Recall that we loosely defined causal determinism as follows, with terms in need of clarification italicized: Determinism: The world is governed by or is under the sway of determinism if and only if, given a specified way things are at a time t, the way things go thereafter is fixed as a matter of natural law.
Then if all—or even just most—events E that are our human actions are causally determined, the problem that matters to us, namely the challenge to free will, is in force. Nothing so global as states of the whole world need be invoked, nor even a complete determinism that claims all events to be causally determined. For example, the start of a football game on TV on a normal Saturday afternoon may be sufficient ceteris paribus to launch Ted toward the fridge to grab a beer; but not if a million-ton asteroid is approaching his house at.
Bertrand Russell famously argued against the notion of cause along these lines and others in , and the situation has not changed. By trying to define causal determination in terms of a set of prior sufficient conditions, we inevitably fall into the mess of an open-ended list of negative conditions required to achieve the desired sufficiency. Moreover, thinking about how such determination relates to free action, a further problem arises. If the ceteris paribus clause is open-ended, who is to say that it should not include the negation of a potential disruptor corresponding to my freely deciding not to go get the beer?
They are also too short. For the typical set of prior events that can intuitively, plausibly be thought to be a sufficient cause of a human action may be so close in time and space to the agent, as to not look like a threat to freedom so much as like enabling conditions.
So we have a number of good reasons for sticking to the formulations of determinism that arise most naturally out of physics. And this means that we are not looking at how a specific event of ordinary talk is determined by previous events; we are looking at how everything that happens is determined by what has gone before.
The state of the world in only entails that Ted grabs a beer from the fridge by way of entailing the entire physical state of affairs at the later time. We will briefly explain some of them. Why take the state of the whole world, rather than some perhaps very large region, as our starting point?
One might, intuitively, think that it would be enough to give the complete state of things on Earth, say, or perhaps in the whole solar system, at t, to fix what happens thereafter for a time at least. But notice that all sorts of influences from outside the solar system come in at the speed of light, and they may have important effects. If no physical influences can go faster than light, then the state of things must be given over a spherical volume of space 1 light-month in radius.
In the time of Laplace, of course, there was no known speed limit to the propagation of physical things such as light-rays. In such a world, evidently, one has to fix the state of things over the whole of the world at a time t, in order for events to be strictly determined, by the laws of nature, for any amount of time thereafter. In all this, we have been presupposing the common-sense Newtonian framework of space and time, in which the world-at-a-time is an objective and meaningful notion.
Below when we discuss determinism in relativistic theories we will revisit this assumption. That is, a specification of the state of the world at a time t, along with the laws, determines not only how things go after t, but also how things go before t. Philosophers, while not exactly unaware of this symmetry, tend to ignore it when thinking of the bearing of determinism on the free will issue. The reason for this is that we tend to think of the past and hence, states of the world in the past as done, over, fixed and beyond our control.
Forward-looking determinism then entails that these past states—beyond our control, perhaps occurring long before humans even existed—determine everything we do in our lives. It then seems a mere curious fact that it is equally true that the state of the world now determines everything that happened in the past. We have an ingrained habit of taking the direction of both causation and explanation as being past—-present, even when discussing physical theories free of any such asymmetry.
We will return to this point shortly. Another point to notice here is that the notion of things being determined thereafter is usually taken in an unlimited sense—i. But conceptually speaking, the world could be only imperfectly deterministic: things could be determined only, say, for a thousand years or so from any given starting state of the world. For example, suppose that near-perfect determinism were regularly but infrequently interrupted by spontaneous particle creation events, which occur only once every thousand years in a thousand-light-year-radius volume of space.
This unrealistic example shows how determinism could be strictly false, and yet the world be deterministic enough for our concerns about free action to be unchanged. Part of understanding determinism—and especially, whether and why it is metaphysically important—is getting clear about the status of the presumed laws of nature.
In the physical sciences, the assumption that there are fundamental, exceptionless laws of nature, and that they have some strong sort of modal force, usually goes unquestioned. We can characterize the usual assumptions about laws in this way: the laws of nature are assumed to be pushy explainers. They make things happen in certain ways , and by having this power, their existence lets us explain why things happen in certain ways.
For a defense of this perspective on laws, see Maudlin Laws, we might say, are implicitly thought of as the cause of everything that happens. If the laws governing our world are deterministic, then in principle everything that happens can be explained as following from states of the world at earlier times.
Interestingly, philosophers tend to acknowledge the apparent threat determinism poses to free will, even when they explicitly reject the view that laws are pushy explainers. Earman , for example, advocates a theory of laws of nature that takes them to be simply the best system of regularities that systematizes all the events in universal history.
Yet he ends his comprehensive Primer on Determinism with a discussion of the free will problem, taking it as a still-important and unresolved issue. Prima facie this is quite puzzling, for the BSA is founded on the idea that the laws of nature are ontologically derivative, not primary; it is the events of universal history, as brute facts, that make the laws be what they are, and not vice-versa. Taking this idea seriously, the actions of every human agent in history are simply a part of the universe-wide pattern of events that determines what the laws are for this world.
It is then hard to see how the most elegant summary of this pattern, the BSA laws, can be thought of as determiners of human actions. The determination or constraint relations, it would seem, can go one way or the other, not both. On second thought however it is not so surprising that broadly Humean philosophers such as Ayer, Earman, Lewis and others still see a potential problem for freedom posed by determinism.
For even if human actions are part of what makes the laws be what they are, this does not mean that we automatically have freedom of the kind we think we have, particularly freedom to have done otherwise given certain past states of affairs.
One might try to defend this claim—unpalatable as it seems intuitively, to ascribe ourselves law-breaking power—but it does not follow directly from a Humean approach to laws of nature.
Instead, on such views that deny laws most of their pushiness and explanatory force, questions about determinism and human freedom simply need to be approached afresh. A second important genre of theories of laws of nature holds that the laws are in some sense necessary. For any such approach, laws are just the sort of pushy explainers that are assumed in the traditional language of physical scientists and free will theorists. But a third and growing class of philosophers holds that universal, exceptionless, true laws of nature simply do not exist.
For these philosophers, there is a simple consequence: determinism is a false doctrine. As with the Humean view, this does not mean that concerns about human free action are automatically resolved; instead, they must be addressed afresh in the light of whatever account of physical nature without laws is put forward.
Determinism requires a world that a has a well-defined state or description, at any given time, and b laws of nature that are true at all places and times. If we have all these, then if a and b together logically entail the state of the world at all other times or, at least, all times later than that given in a , the world is deterministic.
The Epistemology of Determinism How could we ever decide whether our world is deterministic or not? Given that some philosophers and some physicists have held firm views—with many prominent examples on each side—one would think that it should be at least a clearly decidable question. Unfortunately, even this much is not clear, and the epistemology of determinism turns out to be a thorny and multi-faceted issue. Most philosophers and scientists since the 17th century have indeed thought that there are.
But in the face of more recent skepticism, how can it be proven that there are? The first hurdle can perhaps be overcome by a combination of metaphysical argument and appeal to knowledge we already have of the physical world. Philosophers are currently pursuing this issue actively, in large part due to the efforts of the anti-laws minority. The debate has been most recently framed by Cartwright in The Dappled World Cartwright in terms psychologically advantageous to her anti-laws cause.
Those who believe in the existence of traditional, universal laws of nature are fundamentalists; those who disbelieve are pluralists.
A Primer on Determinism