This is the first post in what will hopefully be a series on the history of the Causal Principle (CP), i.e., that anything that begins to exist has a cause. Today, the principle is most frequently discussed in connection with the Kalam Cosmological Argument, where the CP appears as a premise, and in Hume scholarship. However, the CP has enjoyed a broader history, with connections to the free-will debate, explanations for the order we apparently find in our universe, and the nature of both natural and theological necessity. To begin this series, I will examine how Thomas Hobbes defended the CP in his exchange with John Bramhall on the nature of free-will and necessity.

1. The Hobbes-Bramhall Debate

Hobbes was a determinist. For Hobbes, every occurrence is necessitated by whatever came before. Concerning free-will, Hobbes was a compatibilist. That is, for Hobbes, free-will and determinism are compatible. And Hobbes argued that we have free-will. As Hobbes recognized, not all of our actions are free. We perform some of our actions impulsively and some of us are bound up in chains. But Hobbes also recognized that at least some of our actions result from a deliberative process, where we consider the goods and evils that may result from alternative actions. For Hobbes, deliberation involves an “alternative succession of contrary appetites” (Hobbes 1999, pg. 37); the last member in this succession — that is, wherever our deliberation ends — “is that which we call the will” (Hobbes 1999, pg. 37). In other words, our will is the appetite we end up with after a deliberative process. When there are no impediments standing in the way of an agent acting in accord with their will, they are free.

In contrast, libertarians, like Bramhall, are incompatibilists. Incompatibilists hold that free-will and determinism are not compatible. And for libertarians, we are free not only because we have no impediments to acting in accord with our will, but also because we have the power to do otherwise. Before we act, there is nothing that determines what we will do. To explicate the libertarian position, Jean Buridan considers a donkey equidistant between two bails of hay. We are supposed to imagine that there is no reason at all for the donkey to choose one bail as opposed to the other. Yet if the donkey doesn’t choose one bail, the donkey will starve. And we are supposed to think that if the donkey has free-will then, even though nothing at all favors one bail over the other, the donkey will chose one bail over the other. This sort of free-will explicitly violates determinism: the donkey breaks from the chain of preceding causes, choosing one bail over the other, even though, prior to the donkey’s choice, nothing at all determines that the donkey will choose one specific bail as opposed to the other.

2. The Causal Principle and Hobbes’s Determinism

For Hobbes, “nothing takes beginning from itself” (Hobbes 1999, pg. 38). Suppose that an agent comes to have a will that they did not previously have. In that case, the agent’s will began to exist. Since “nothing takes beginning from itself”, the will cannot be its own cause. And since wills are not self-caused, they are either caused by some other or they are uncaused. Given the CP, nothing that begins to exist — including wills — can be uncaused. So, Hobbes concludes, wills must be caused by some other. But how does Hobbes defend the CP? Here’s how Hobbes puts the argument:

[…] that a man cannot imagine anything to begin without a cause, can no other way be made known but by trying how he can imagine it. But if he try, he shall find as much reason, if there be no cause of the thing, to conceive it should begin at one time as at another, that is, he has equal reason to think it should begin at all times; which is impossible, and therefore he must think there was some special cause why it began then rather than sooner or later; or else that it began never, but was eternal (Hobbes 1999, pp. 39-40).

In sum, Hobbes has argued that the falsity of the CP is inconceivable. To establish that the falsity of the CP is inconceivable, Hobbes invites us to imagine a counterexample to the CP, that is, a state of affairs where at least one thing begins without a cause. Present day philosophers may be tempted to read ‘thing’ in a restricted sense, e.g., perhaps the CP only tells us that entities — but not events or changes — have causes. Seventeenth century philosophers understood the issue in broader terms, i.e., the CP tells us that no entities, events, or changes begin without causes. The resulting state of affairs is inconceivable. However, there are two distinct interpretations of Hobbes’s statement that “he has equal reason to think it should begin at all times; which is impossible”. On a first interpretation, Hobbes is claiming that it’s inconceivable for there to be equal reason for a thing to begin at all times. There must be a reason that picks out one specific time. On a second interpretation, Hobbes is saying that while it’s inconceivable for a thing to begin at all times, that would have been the result if things could begin without a cause. On the first interpretation, what’s at issue is whether there can be equal reason for a thing to begin at all times, even though the thing does not begin at all times, and, on the second, what’s at issue is whether there being a reason for a thing to begin at all times entails that the thing does begin at all times.

Evidence for the first interpretation can be found in chapter 12 of Hobbes’s Leviathan. Hobbes explicates the factors that naturally dispose human beings to religious belief. Hobbes writes that “upon the sight of anything that hath a Beginning” we are disposed “to think it had a cause, which determined the same to begin, then when it did, rather than sooner or later” (Hobbes 2009, pg 91). Hobbes goes on to tell us that our natural inclination to think that things begin for the sake of a cause, when coupled with our anxieties concerning “death, poverty, or other calamity” (Hobbes 2009, pg 92), inspire belief in various invisible agents, such as the pagan gods or nymphs. However, “the desire men have to know the causes of natural bodies, and their several virtues and operations” can lead us to acknowledge the “one God eternal, infinite, and omnipotent” (Hobbes 2009, pg. 92). In other words, while our natural disposition to think that beginnings have causes can lead us astray, it doesn’t need to. For Hobbes, we have no choice but to conceive of natural bodies as having causes, even if we are sometimes led astray as to the identity of those causes; given a disposition to think that anything that begins is determined to begin at some specific time by a cause, it may be impossible for us to conceive that anything could begin at an arbitrary time without a cause.

Evidence for the second interpretation can be found in Hobbes’s De Corpore. In the relevant passage, Hobbes argues that anything that begins to move must be moved by some other. If something could move without some other, then there is equal reason for an entity to move in any direction:

[…] seeing it was supposed that nothing is out of it [i.e., nothing external that gives it motion], the reason of its motion one way would be the same with the reason of its motion every other way, wherefore it would be moved alike all ways at once; which is impossible (Hobbes 1839, pg. 115; also see Cromartie 2008).

Elsewhere in De Corpore, Hobbes argues that any body, once in motion, will continue in motion unless some other causes its motion to cease. In that case, Hobbes argues that if nothing causes the motion to cease,

there will be no reason why it should rest now, rather than at some other time; wherefore its motion would cease in every particle of time alike; which is not intelligible (Hobbes 1839, pp. 115-6).

These two passages strongly suggest the second interpretation. For Hobbes, the reason that the beginning of the motion of a body requires a cause is that otherwise all directions would be equal and so the body would move simultaneously in all directions. And the reason that the cessation of motion requires a cause is that otherwise there would be equal reason for motion to stop at every instant of time and then motion would stop at every instant of time. A body cannot move simultaneously in all directions, so all motion requires a cause to begin to exist; likewise, a body’s motion cannot stop at all instants of time, so the cessation of motion requires a cause. Since Hobbes understood the CP to refer to entities, events, changes, and so on, Hobbes is effectively applying a specific instance of the CP — no thing (e.g., motion, rest) can begin without a cause to direct that thing in a specific way (e.g., in a specific direction or at a specific time). A body simultaneously moving in all directions or ceasing its motion equally at all times are equally as impossible as a thing beginning to exist at all times. So, the reason that the beginning of a thing requires a cause is that otherwise all times would be equal and so the thing would begin to exist at all times.

It’s difficult to understand why there being equal reason for a thing to begin at any time or for a body to begin motion in any direction would entail that the thing would begin at all times or in all directions. But perhaps what Hobbes has in mind is that things behave as they do because they have the most reason to do so. A donkey, equidistant between two bails of hay, either eats both simultaneously (impossible) or doesn’t eat. A body, with equal reason to begin motion in two numerically distinct directions, begins motion in both directions (impossible) or doesn’t begin to move. A thing, with equal reason to begin at two numerically distinct instants of time, begins at both instants (impossible) or doesn’t begin. If this is the right way to understand Hobbes, we can also understand the end of Hobbes’s defense of the CP. As Hobbes writes, either “there was some special cause why it began then rather than sooner or later; or else that it began never, but was eternal”. That is, if there is no cause that picks out a specific time and a thing cannot begin at all times, then the thing never begins at all.

In other words, Hobbes appears committed to a version of the Principle of Sufficient Reason — roughly, that there is a sufficient reason for everything that happens — and, on its basis, rejects the notion that something can happen without a cause as incoherent. There cannot be sufficient reason (for example) for a thing to begin to exist at every time that there has been or will be, since, if there were, the thing would begin at every instant that there has been or will be.

We can also explain the supposed evidence for the first interpretation that we found in Leviathan. Things begin when and how they do because they have the most reason to do so. Since only causes can provide appropriately selective reasons — only causes can uniquely select when and how things begin — we cannot conceive of things beginning without causes. Since everything that begins has a cause, we come to one eternal thing, God, that determined when and how everything else began, but did not itself begin. Hence, “the desire men have to know the causes of natural bodies, and their several virtues and operations” can lead us to acknowledge the “one God eternal, infinite, and omnipotent” (Hobbes 2009, pg. 92).

Lastly, while we can explain the evidence for the first interpretation in terms of the second interpretation, there seems to be no plausible way to explain the evidence for the second interpretation in terms of the first.

Thus, we can summarize Hobbes’s argument:

1. If something could begin without a cause, then there would be equal reason for a thing to begin at any arbitrary time.

2. There isn’t equal reason for a thing to begin at any arbitrary time.

3. So, anything that begins to exist has a cause (modus tollens from 1, 2).

4. So, wills begin to exist.

5. Wills have a cause (universal instantiation and modus ponens from 3, 4).

6. Either wills cause themselves to begin or wills are caused by some other.

7. Nothing causes itself to begin (i.e., nothing takes beginning from itself).

8. So, wills do not cause themselves (universal instantiation from 7).

9. Therefore, wills are caused by some other (modus tollendo tollens from 6, 8).

This argument is logically valid, so that if the premises are true, the conclusion must be true. Libertarians reply that this argument poses no threat to their view; since they allow for indeterministic causation, they maintain that wills are caused without being deterministically caused. But I am focused on Hobbes’s case for the CP and not in whether Hobbes has provided a good case against libertarianism. Hence, I am interested in whether we have good reason to believe the first two premises.

3. Why the First Premise?

According to Hobbes’s first premise, if something could begin without a cause, then there would be equal reason for a thing to begin at any arbitrary time. In other words, had the CP been false, there would have been a violation of the Principle of Sufficient Reason. Unfortunately, I have been unable to find anywhere that Hobbes offers an explicit argument for the first premise. To attempt to answer why Hobbes endorsed this premise, I need to first articulate Hobbes’s conception of causation and then show why, given how Hobbes construes causation, had the CP been false, there would be equal reason for things to begin at any instant of time.

On Hobbes’s conception of causation, (i) causation involves an agent and a patient, (ii) agents produce changes in patients, and (iii) the changes that agents produce in patients are local motions (Leijenhorst 1996). Both the agent and patient are bodies. When an agent acts on a patient, an accident is produced in the patient. The accident that is produced in the patient is the effect (Hobbes 1839, pg. 120). The specific effect produced in the patient depends upon the accidents had by both the agent and the patient. For example, fire warms because of an accident — e.g., hotness — in the fire (Hobbes 1839, pg. 121). If any one of the accidents requisite for an effect is not present in the agent, then the effect is not produced (Hobbes 1839, pg. 121).

Perhaps Hobbes had in mind an argument like the following. For Hobbes’s scholastic interlocutors, there are four reasons (or aitia) for anything to obtain, i.e., the efficient, material, final, and formal causes. Hence, Hobbes’s interlocutors maintained that, insofar as there is a reason for something to begin at any one time, as opposed to all others, that reason must be either an efficient, material, final, or formal cause, or else some combination thereof.

For Hobbes, the essence of x is not the efficient cause of x; instead, the essence is the efficient cause of our knowledge of x (Hobbes 1839, pp. 131-132). Ends (or final causes) have “no place but in such things as have sense and will” (Hobbes 1839, pg. 132). Hence, for Hobbes, essences and ends have no application to things independent of our knowledge of them and that, themselves, lack sense or will. Since there are many things that begin to exist without being objects of knowledge and that lack sense or will, the final and formal causes cannot generally explain why things begin to exist.

Having ruled out the final and formal causes as the general reason that that something could begin to exist, insofar as things begin for reasons, they begin for the sake of the efficient and material causes. Hobbes defined the total cause as the combination of the material and efficient causes, where the material cause consists of the aggregate of accidents in the patient necessary for the effect (Hobbes 1839, pg 122) and the efficient cause consists of the aggregate of accidents in the agent necessary for the effect (Hobbes 1839, pg. 122). The total cause is then the “aggregate of all the accidents of both of the agents how many soever they may be, and of the patient together” (Hobbes 1839, pp. 121-122). Therefore, insofar as there is a reason for a thing to begin at any one time as opposed to any other, that reason must be a total cause. Ergo, if something could begin without a total cause, then there wouldn’t be a reason for the thing to begin to exist at any one time as opposed to any other. In that case, there would be equal reason — that is, no reason — for a thing to begin at any arbitrary time.

Hobbes may also have been committed to a secondary argument. When all of the accidents are collectively together in both the agent and patient, it is inconceivable for the effect to not be produced. And when any accident that is part of the entire cause is lacking from either the agent or the patient, then the effect will not be produced (Hobbes 1839, pp. 121-122). An entire cause is always both necessary and sufficient for its effect, so that whenever the entire cause is present, the effect must follow (Hobbes 1839, pp. 121-122). Hence, when a total cause produces its effect, an appropriate set of accidents must be present in both the agent and the patient; for something to begin without a total cause would involve something beginning to exist even when the appropriate set of accidents are not present in both the agent and the patient. And therefore no accident would select some one time as the appropriate time for the thing to begin.

Likewise, we have explanations for the other Hobbesian arguments I’ve examined; for example, if a thing can begin to move without a cause to select a specific direction, then there wouldn’t be a combination of accidents that selected the direction. There’d be no reason that some one direction is selected over others. And since whatever accidents are present suffice for whatever effect transpires, either the new thing begins to exist in all ways or times equally, or doesn’t begin at all.

4. Beginnings Without Causes in Classical Physics

According to the first premise, if something can begin without a cause, then there is equal reason for a thing to begin at any arbitrary time. This premise is false just in case, at all of the nearest possible worlds where something begins without a cause, it’s not true that there is equal reason for a thing to begin at any arbitrary time. In the actual world, the fundamental laws are not those known in the seventeenth century. Hobbes’s mechanical conception of causation — where bodies bring about changes in the motion of other bodies via direct contact — is entirely alien to contemporary physical theory. When things begin in the actual world, they do not do so for the sake of Hobbesian causes. Hence, the CP, as Hobbes conceived of it, is false.

4.1. Norton’s Dome

We can ask a more interesting question. Supposing that some sophisticated version of seventeenth century physics had turned out to be true of the actual world, would it then have been true that, if something can begin without a cause, there is equal reason for a thing to begin at any arbitrary time? Again, on standard accounts of the truth conditions of counterfactuals, the truth of a counterfactual conditional should be evaluated by considering whether the consequent is true at the nearest possible worlds where the antecedent is true. If classical mechanics had turned out to be correct, then all of the worlds where the laws of classical mechanics are true would be closer by than all of the worlds where the laws of classical mechanics are false. Hence, if the following two statements turn out to be true:

1. There are worlds where the laws of classical mechanics are true and yet some things begin without causes and

2. In those worlds, there isn’t equal reason for a thing to begin at any arbitrary time

then we have a good reason to reject premise 1 in my reconstruction of Hobbes’s argument. And it turns out that these two statements are both true.

There are models in classical physics where, though the model satisfies the laws, it’s false that all things that begin have a Hobbesian cause. Following John Norton (2003, 2008), suppose a ball is rolling up the surface of a dome (with a shape specified in Norton’s original paper) in a uniform gravitational field. If the ball has precisely the right kinetic energy at the start, then the ball will come to rest at the top of the dome. But the laws of classical mechanics are time reversal invariant, so that the time reversed scenario equally satisfies the laws. A ball sits atop a dome at rest; sometime in the future, the ball spontaneously begins rolling down the dome. If we start with the ball atop the dome at t=0, then the ball beginning to roll down the dome at any time T, where T > t, is consistent with the laws of classical mechanics.

If the ball has been atop the dome for all eternity past, then there is equal reason for the ball to begin to move at any time. Perhaps Hobbes could have seen this as a vindication of his view. But notice that we can easily use Norton’s dome to construct scenarios where there isn’t equal reason for the ball to move at any time. For example, consider a possible world where a ball travels up a dome and comes to rest at the top of the dome at time t = 0. In that case, the ball can only begin to roll down the dome after t = 0. Contra Hobbes, all times wouldn’t be equal. Or suppose that the dome exists only during the interval between t = -1 and t = 1. In that case, assuming the ball reaches the dome’s top at t = 0, the ball can begin to roll down the dome uncaused only between t = 0 and t = 1. Again, all times wouldn’t be equal.

Hobbes could object that even though not all times are equal, all of the times within a specific interval are equal. And then Hobbes can reiterate his argument in terms of the equality of times within an interval. This objection does not work. Whatever happens is constrained by physical law. Hence, whatever happens must be described by one of the solutions to the laws. As a matter of logical necessity, there are no solutions where the ball’s motion begins at more than one instant. Hence, even without the CP, the ball will not begin its motion at more than one instant.

Some readers will be tempted to object that when the ball begins to roll down the dome, no thing begins to exist. But recall that, for Hobbes, we should interpret ‘thing’ as broadly as possible; after all, wills are more like characteristics of an agent and are not, for Hobbes, objects unto themselves. Hence, if the CP is construed broadly enough so that it applies to wills, then the CP should also apply to the ball’s beginning to move.

Other readers may be tempted to object that the ball’s motion could be indeterministically caused. This objection is not available to Hobbes for two reasons. First, Hobbes rejected indeterministic causation. Second, Hobbes conceived of causation in terms of both an agent and a patient, yet there is no agent that produces the ball’s motion. So, Hobbes’s view entails that the ball’s motion is uncaused.

4.2. Causal Asymmetry

The first counterexample depended upon the fact that there are indeterministic models of classical mechanics. However, there are also deterministic models of classical mechanics that appear inconsistent with Hobbesian causes. Hobbes argues that causes must always precede their effects in time (Martinich 2017, pg. 307). Here, I follow Martinich’s brief summary of Hobbes’s argument. There are three possibilities: causes precede their effects in time, causes are simultaneous with their effects, or else effects precede their causes in time. Suppose that causes are simultaneous with their effects. In that case, either there is a time when the cause exists without the effect or not. If there is a time when the cause exists without the effect, then the cause is not simultaneous with the effect. Contradiction. The alternative is that the cause can only exist at the times when the effect exists and vice versa. That can’t be either, since children can outlive their parents. Hence, causes cannot be simultaneous with their effects. Moreover, effects cannot exist before causes because, if the effect already exists, then there is no need for the cause. Therefore, causes must precede their effects in time.

Contrary to Hobbes, the dynamical laws found in classical physics are symmetric with respect to time. Hence, the dynamical laws found in classical physics do not support temporally asymmetric necessitation relations of the sort Hobbes imagines. Consider two sets of possible worlds that satisfy the classical laws. First, there are worlds where the direction of time is not fundamental. In those worlds, nothing fundamentally begins to exist, and the CP may be trivially satisfied. Second, there are worlds where the direction of time is fundamental, but, even so, the laws are temporally symmetric, so that there is no fundamental temporal asymmetry of causal influence. In those worlds, the CP is violated, even though determinism still obtains. Ergo, in the closest worlds where the CP is violated, a Hobbesian equality among times does not obtain.

Conclusion

In his debate with Bramhall, Hobbes appeals to a version of the Principle of Sufficient Reason to defend the CP. If a thing could begin without a cause, then the thing would have equal reason to begin at every instant of time. But a thing cannot begin at every instant of time. In reply, there are models of classical mechanics incompatible with Hobbesian causes. First, there are indeterministic models, where some changes, e.g., the ball beginning to move on Norton’s dome, that cannot result from a Hobbesian cause. Hobbes would be wrong to object that the ball’s motion can equally begin in all times. There may be a specific temporal window within which the ball’s motion must begin insofar as the motion begins at all. Hobbes is also wrong to say that a thing could begin at every instant of time; whatever happens satisfies the laws, there are no models of the laws where the ball’s motion begins at every instant, and so — independent of the truth of the CP — the ball will not begin its motion at every instant. On the other hand, there are deterministic models where events occur without Hobbesian causes. This is because classical mechanics does not include a temporal asymmetry of causal influence and, hence, should not include Hobbes’s distinction between agents and patients.

References

Alan Cromartie, 2008, “The God of Thomas Hobbes”, The Historical Journal 51(4), pp. 857-879.

Thomas Hobbes, 1839, “Concerning Body”. In William Molesworth (Ed.), The English Works of Thomas Hobbes of Malmesbury, Vol. I.

Thomas Hobbes, 1999, “Of Liberty and Necessity”. In V. Chappell (Ed.), Hobbes and Bramhall on Liberty and Necessity, Cambridge University Press, pp. 15–42.

Thomas Hobbes, 2009, Leviathan, or the Matter, Forme and Power of a Commonwealth Ecclesiastical and Civil. Regnery Publishing, Inc.

Cees Leijenhorst, 1996, “Hobbes’s Theory of Causality and Its Aristotelian Background”, The Monist 79(3), pp. 426-447.

A.P. Martinich, 2017, “Thomas Hobbes and John Bramhall”, In Kevin Timpe, Meghan Griffith, & Neil Levy (Eds.), The Routledge Companion to Free Will, Routledge, pp. 303-312.

John Norton, 2003, “Causation as Folk Science”, Philosophers’ Imprint 3(4), pp. 1-22.

John Norton, 2008, “The Dome: An Unexpectedly Simple Failure of Determinism”, Philosophy of Science 75(5), pp. 786-798.