Why do physical laws exist

This is an area where work on laws needs to be done. But, at the very least, these claims cannot be quite right. As the discussion above illustrates, Sober, Lange and others have argued that even generalizations known to be accidental can be confirmed by their instances. Dretske and Armstrong need some plausible and suitably strong premise connecting lawhood to confirmability and it is not clear that there is one to be had.

Here is the basic problem: As many authors have noticed e. So much so that, with background beliefs of the right sort, just about anything can be confirmed irrespective of its status as a law or whether it is lawlike.

Thus, stating a plausible principle describing the connection between laws and the problem of induction will be difficult. Philosophers have generally held that some contingent truths are or could be laws of nature. Furthermore, they have thought that, if it is a law that all F s are G s, then there need not be any metaphysically necessary connection between F -ness and G -ness, that it is metaphysically possible that something be F without being G.

The latter world is also a world where inertia is instantiated but does not necessitate zero acceleration. Some necessitarians , however, hold that all laws are necessary truths.

See Shoemaker and , Swoyer , Fales , Bird See Vetter for criticism of Bird from within the dispositional essentialist camp. Others have held something that is only slightly different. Maintaining that some laws are singular statements about universals, they allow that some laws are contingently true.

Still, this difference is minor. Two reasons can be given for believing that being a law does not depend on any necessary connection between properties. The first reason is the conceivability of it being a law in one possible world that all F s are G s even though there is another world with an F that is not G. The second is that there are laws that can only be discovered in an a posteriori manner. If necessity is always associated with laws of nature, then it is not clear why scientists cannot always get by with a priori methods.

Naturally, these two reasons are often challenged. The necessitarians argue that conceivability is not a guide to possibility. In further support of their own view, the necessitarians argue that their position is a consequence of their favored theory of dispositions, according to which dispositions have their causal powers essentially. So, for example, on this theory, charge has as part of its essence the power to repel like charges.

Laws, then, are entailed by the essences of dispositions cf. As necessitarians see it, it is also a virtue of their position that they can explain why laws are counterfactual-supporting; they support counterfactuals in the same way that other necessary truths do Swoyer , ; Fales , 85— The primary worry for necessitarians concerns their ability to sustain their dismissals of the traditional reasons for thinking that some laws are contingent.

The problem cf. Prima facie, there is nothing especially suspicious about the judgment that it is possible that an object travel faster than light.

How is it any worse than the judgment that it is possible that it is raining in Paris? Another issue for necessitarians is whether their essentialism regarding dispositions can sustain all the counterfactuals that are apparently supported by laws of nature Lange Going back to Armstrong , 40 , there have been challenges to those who hold a Humean account of laws, and about whether Humean laws are explanatory.

More recently, Maudlin has put the challenge in a perspicuous way:. If one is a Humean, then the Humean Mosaic itself appears to admit of no further explanation. Since it is the ontological bedrock in terms of which all other existent things are to be explicated, none of these further things can really account for the structure of the Mosaic itself. This complaint has been long voiced, commonly as an objection to any Humean account of laws.

If the laws are nothing but generic features of the Humean Mosaic, then there is a sense in which one cannot appeal to those very laws to explain the particular features of the Mosaic itself: the laws are what they are in virtue of the Mosaic rather than vice versa Maudlin , Loewer , offers a response to the issue that Maudlin highlights. The move he makes to avoid the circularity is that Humean laws do not metaphysically explain elements of the mosaic, but they do scientifically explain aspects of the mosaic, suggesting that there are two notions of explanation and so no circularity.

An increasingly popular way to look at the relation between laws and their instances is taking instances as grounding laws. No individual instance of a law can fully ground the law, but a conjunction of instances does more fully ground the law.

Another plausible way of viewing the relation between laws and their instances is to see laws as grounding their instances Emery Because the grounding relation is non-symmetric, both of these views cannot be true.

The way out of this dilemma is one that illuminates the debate about explanation in an interesting way. This is because the content of the explanandum what is to be explained is embedded in the content of the explanans what is intended to do the explaining , and something cannot explain itself or be an essential part of an explanation of itself.

Notice that this formulation exposes the problem: if the explanans includes the explanandum as part of its content, it makes the explanation devoid of understanding. Ones audience would have to already have had an understanding of the explanandum. Successful explanations are not circular, so anyone taking laws as grounds for their instances ought not to think that the grounding relation is explanatory.

The point here is not to show that grounding is not an explanatory relation, but rather to show that laws of nature are not suited to explain their instances. Circularity also infects the DN model of explanations. As the authors of the DN model pointed out:. The issue here undermines the importance of the role for explanations to provide understanding.

The required validity brings semantic circularity, because the content of the explanans would then be sufficient for the truth of the explanandum. Indeed, at least one law needs to be essential to the validity of the argument, and the laws being part of the explanans are clearly a factor regarding the circularity. To add to these challenges, it is good to remember what Dretske pointed out regarding laws and explanation. To say that a law is a universal truth having explanatory power is like saying a chair is a breath of air used to seat people.

None , Instead, it was thought that laws had to be a different kind of thing: a relation between universals, physically necessary generalizations, or a true axiom or theorem of an ideal system, or even a metaphysically necessary generalization. This is an approach that identifies what sort of entity a law of nature is. Two separate but related questions have received much recent attention in the philosophical literature surrounding laws.

Neither has much to do with what it is to be a law. Instead, they have to do with the nature of the generalizations scientists try to discover. First: Does any science try to discover exceptionless regularities in its attempt to discover laws?

Second: Even if one science — fundamental physics — does, do others? Philosophers draw a distinction between strict generalizations and ceteris-paribus generalizations.

The contrast is supposed to be between universal generalizations of the sort discussed above e. The idea is that the former would be contradicted by a single counterinstance, say, one accelerating inertial body, though the latter is consistent with there being one smoker who never gets cancer. Though in theory this distinction is easy enough to understand, in practice it is often difficult to distinguish strict from ceteris-paribus generalizations. This is because many philosophers think that many utterances which include no explicit ceteris-paribus clause implicitly do include such a clause.

For the most part, philosophers have thought that if scientists have discovered any exceptionless regularities that are laws, they have done so at the level of fundamental physics.

A few philosophers, however, are doubtful that there are exceptionless regularities at even this basic level. For example, Cartwright has argued that the descriptive and the explanatory aspects of laws conflict. But if that is what the law says then the law is not an exceptionless regularity. The statement of the gravitational principle can be amended to make it true, but that, according to Cartwright, at least on certain standard ways of doing so, would strip it of its explanatory power.

Lange uses a different example to make a similar point. If this expression were used to express the strict generalization straightforwardly suggested by its grammar, then such an utterance would be false since the length of a bar does not change in the way described in cases where someone is hammering on the ends of the bar. It looks like the law will require provisos, but so many that the only apparent way of taking into consideration all the required provisos would be with something like a ceteris-paribus clause.

Then the concern becomes that the statement would be empty. Even those who agree with the arguments of Cartwright and Lange sometimes disagree about what ultimately the arguments say about laws. Cartwright believes that the true laws are not exceptionless regularities, but instead are statements that describe causal powers. So construed, they turn out to be both true and explanatory.

Lange ends up holding that there are propositions properly adopted as laws, though in doing so one need not also believe any exceptionless regularity; there need not be one. So, he concludes that there are no laws. Earman and Roberts hold that there are exceptionless and lawful regularities. More precisely, they argue that scientists doing fundamental physics do attempt to state strict generalizations that are such that they would be strict laws if they were true:.

Cartwright argues that there is no such component force and so thinks such an interpretation would be false. Earman and Roberts disagree.

In any case, much more would need to be said to establish that all the apparently strict and explanatory generalizations that have been or will be stated by physicists have turned or will turn out to be false. Earman, et al. Supposing that physicists do try to discover exceptionless regularities, and even supposing that our physicists will sometimes be successful, there is a further question of whether it is a goal of any science other than fundamental physics — any so-called special science — to discover exceptionless regularities and whether these scientists have any hope of succeeding.

Consider an economic law of supply and demand that says that, when demand increases and supply is held fixed, price increases. Notice that, in some places, the price of gasoline has sometimes remained the same despite an increase in demand and a fixed supply, because the price of gasoline was government regulated.

It appears that the law has to be understood as having a ceteris-paribus clause in order for it to be true. This problem is a very general one. As Jerry Fodor , 78 has pointed out, in virtue of being stated in a vocabulary of a special science, it is very likely that there will be limiting conditions — especially underlying physical conditions — that will undermine any interesting strict generalization of the special sciences, conditions that themselves could not be described in the special-science vocabulary.

He gave an argument specifically directed against the possibility of strict psycho-physical laws. More importantly, he made the suggestion that the absence of such laws may be relevant to whether mental events ever cause physical events.

This prompted a slew of papers dealing with the problem of reconciling the absence of strict special-science laws with the reality of mental causation e.

Progress on the problem of provisos depends on three basic issues being distinguished. Obviously, to be a true completion, it must hold for all P , whether P is a strict generalization or a ceteris-paribus one. Second, there is also a need to determine the truth conditions of the generalization sentences used by scientists.

Third, there is the a posteriori and scientific question of which generalizations expressed by the sentences used by the scientists are true. The second of these issues is the one where the action needs to be. On this score, it is striking how little attention is given to the possible effects of context. This might be the case despite the fact that the same sentence uttered in a different context say, in a discussion among fundamental physicists or better yet in a philosophical discussion of laws would result in a clearly false utterance.

These changing truth conditions might be the result of something as plain as a contextual shift in the domain of quantification or perhaps something less obvious. Whatever it is, the important point is that this shift could be a function of nothing more than the linguistic meaning of the sentence and familiar rules of interpretation e.

Maybe not. Notice that the student comes off sounding a bit insolent. In all likelihood, such an unusual situation as someone hammering on both ends of a heated bar would not have been in play when the professor said what he did.

In fact, the reason the student comes off sounding insolent is because it seems that he should have known that his example was irrelevant. Indeed, they are rarely used in this way. If special scientists do make true utterances of generalization sentences sometimes ceteris-paribus generalization sentences, sometimes not , then apparently nothing stands in the way of them uttering true special-science lawhood sentences.

The issue here has been the truth of special-science generalizations, not any other requirements of lawhood.

How will matters progress? How can philosophy advance beyond the current disputes about laws of nature? Three issues are especially interesting and important ones. The first concerns whether lawhood is a part of the content of scientific theories. This is a question often asked about causation, but less frequently addressed about lawhood. Roberts offers an analogy in support of the thought that it is not: It is a postulate of Euclidean geometry that two points determine a line.

But it is not part of the content of Euclidean geometry that this proposition is a postulate. Euclidean geometry is not a theory about postulates; it is a theory about points, lines, and planes … , This may be a plausible first step toward understanding the absence of some nomic terms from formal statements of scientific theories.

The second issue is whether there are any contingent laws of nature. Necessitarians continue to work on filling in their view, while Humeans and others pay relatively little attention to what they are up to; new work needs to explain the source of the underlying commitments that divide these camps.

Finally, more attention needs to be paid to the language used to report what are the laws and the language used to express the laws themselves and whether the laws explain. It is clear that recent disputes about generalizations in physics and the special sciences turn on precisely these matters, but exploring them may also pay dividends on central matters regarding ontology, realism vs. Portions of the update to this entry were drawn directly from the introduction to Carroll The original version of this entry served as a basis for that introduction.

Thanks to Arnold Koslow for a helpful correction. Thank you to my student research assistant, Chase Dill, for searching out sources and providing good philosophical insight. Ann Rives provided excellent proofreading. The Basic Question: What is it to be a Law?

Systems 3. Universals 4. Humean Supervenience 5. Antirealism 6. Antireductionism 7. Induction 8. They each pick their favorite recipe, shop at the local specialty store, and carefully follow the instructions. But when they take their dishes out of the oven, they are in for a big surprise. The two meals turn out to be identical. We can imagine the existential questions Alice and Bob must ask themselves. How can different ingredients produce the same dish?

What does it even mean to cook Chinese or Italian? And is their approach to preparing food totally flawed? This is exactly the perplexity experienced by quantum physicists.

They have found many examples of two completely different descriptions of the same physical system. In the case of physics, instead of meats and sauces, the ingredients are particles and forces; the recipes are mathematical formulas encoding the interactions; and the cooking process is the quantization procedure that turns equations into the probabilities of physical phenomena.

Just like Alice and Bob, quantum physicists wonder how different recipes lead to the same outcomes. Did nature have any choice in picking its fundamental laws? Albert Einstein famously believed that, given some general principles, there is essentially a unique way to construct a consistent, functioning universe. The current Standard Model of particle physics is indeed a tightly constructed mechanism with only a handful of ingredients. Yet instead of being unique, the universe seems to be one of an infinitude of possible worlds.

Furthermore, the Standard Model comes with 19 constants of nature — numbers like the mass and charge of the electron — that have to be measured in experiments. On the one hand, particle physics is a wonder of elegance; on the other hand, it is a just-so story.

If our world is but one of many, how do we deal with the alternatives? Modern physicists embrace the vast space of possibilities and try to understand its overarching logic and interconnectedness.

From gold diggers they have turned into geographers and geologists, mapping the landscape in detail and studying the forces that have shaped it. The game changer that led to this switch of perspective has been string theory. At this moment it is the only viable candidate for a theory of nature able to describe all particles and forces, including gravity, while obeying the strict logical rules of quantum mechanics and relativity.

The good news is that string theory has no free parameters. It has no dials that can be turned. The absence of any additional features leads to a radical consequence. All numbers in nature should be determined by physics itself. Which brings us to the bad news. This is not unusual in physics.

We traditionally distinguish between fundamental laws given by mathematical equations, and the solutions of these equations.

GPS relies on the most accurate timing devices we currently possess: atomic clocks. These count the passage of time according to frequency of the radiation that atoms emit when their electrons jump between different energy levels. Why go to all this bother?

The point is that the researchers did not just pick on a random constant. Planck said that a light quantum has an amount of energy equal to the frequency of the light multiplied by h. But Albert Einstein argued five years later that the trick must be taken literally: light really is chopped up into these discrete packets of energy. The reason why Kentosh and Mohageg asked whether h is really constant, however, is not just because it is a central number for modern physics, but because h also appears in the expression for another fundamental constant, called the fine-structure constant.

This measures the strength of interactions between light and matter, or equivalently, how strong electrical and magnetic forces are. It can be expressed as a combination of three constants: the charge on an electron, the speed of light, and h. And here is the crux: some scientists have suggested that the fine structure constant might not be constant, but could vary over time and space.

In , a team of astronomers using a telescope in Hawaii reported that measurements of light absorbed by very distant galaxy-like objects in space called quasars — which are so far away that we see them today as they looked billions of years ago — suggest that the value of the fine-structure constant was once slightly different from what it is today. That claim was controversial, and still unproven. But if true, it must mean that at least one of the three fundamental constants that constitute it must vary.

Kentosh and Mohageg fixed on h , and specifically on whether h depends on where not when you measure it.