Thursday, July 26, 2018

Random determinism

1. One of the dividing lines in historical theology is the difference between freewill theism (e.g. open theism, simple foreknowledge Arminianism) and predestinarian traditions (e.g. Calvinism, classical Thomism, Augustinianism, Jansenism). Molinism tries to split the difference, combining elements of predestination and meticulous providence with libertarian freedom. 

In my experience, freewill theists, at least the internet variety, typically classify Calvinism as committed to "causal determination". That's become a rhetorical trope. 

Conversely, there's an attempt in some quarters (e.g. Richard Muller, Oliver Crisp) to promote "libertarian Calvinism". I think that's confused on both historical and philosophical grounds.

2. Determinism and indeterminism are usually treated as opposites. Contrasting or contrary principles.

On the one hand, the natural world generally–perhaps invariably–operates according to physical determinism. Like a machine.  

A possible exception is quantum events. There are, however, deterministic interpretations of quantum mechanics. And even if quantum events are physically determinate, they could still be predestined (since predestination isn't a physical determinant). 

In the popular imagination, dynamic systems are indeterminate. However, from what I've read, the key distinction in chaos theory isn't indeterminism but nonlinearity. Dynamic systems are, in fact, deterministic, but nonlinear:

Indeterminism is often related to randomness. A classic example is throwing dice. The outcomes are random in the sense that if the dice are fair, each throw of the dice is causally disconnected from the preceding or succeeding throw of the dice. 

However, the outcome isn't uncaused. It's unpredictable because there are too many variables to consider. Yet the outcome remains determinate. 

3. At the other end of the spectrum, God is the freest entity in the world. God's actions are indeterminate in the sense that nothing absolutely causes God to choose one way or another–although God has reasons for his choices. 

This is sometimes taken to imply that God's choice of which world to create (or not create) is arbitrary. However, God isn't forced to choose between different options, since God can instantiate multiple options (i.e. a multiverse). So there's no dilemma. 

4. One neglected consideration is that the same outcome can be both random and determinate. That might seem counterintuitive, but it's a familiar principle. Consider algorithms to generate randomized outcomes. To my knowledge, that's central to encryption technologies.

Or take a state lottery, which is random by design. Computerized randomization. 

But that's deterministic randomness. The system is designed to ensure random results. You might say it's "rigged", but rigged to guarantee random numbers. In that respect, randomness isn't synonymous with indeterminism. In theory, the world might contain genuinely random events, but still be thoroughly deterministic. 


  1. I would also add that there's functionally no difference between a random and a pseudo-random result, at least as far as humans are concerned. Pseudo-random numbers are used for video games and so forth, and because we cannot calculate what number will be chosen in advance, they are completely unpredictable to us. But I'd go further and say that if you got a sequence of numbers from a random source (such as from radioactive decay) and compared it to a list from a pseudo-random source, it would be impossible for you to tell the difference between the two.

    Whatever else may be the case with "genuine" random number generators, pseudo-random generators are clearly determined, since if you use the same seed you get the same result each time.

    1. Good post and good comment!

      If I can attempt to add my pittance to this fascinating discussion:

      1. Not only are PRNGs deterministic as evidenced in using the same seed leading to the same result as Peter pointed out, as well as the fact that PRNGs are based on algorithms, but even the components of PRNGs are deterministic yet random too. For instance, like all programs, PRNGs can be "periodic". That is, PRNGs cycle through or loop at some point. However, the periods in modern PRNGs (e.g. the Mersenne twister) are typically so long that it's impossible for humans to tell where their cycles end, where they continue, and so on (e.g. suppose they're based on a Mersenne prime 2^19937−1). In short, it's impossible for humans to discern let alone predict a pattern in a PRNG's period, even though a PRNG's period is deterministic.

      2. Speaking of radioactive decay, maybe another example is that we don't know when an individual atom in a radioactive isotope will begin to decay, yet it's straightforward to calculate the amount of radiation emitted by a radioactive isotope.

      3. Maybe another example is, prior to the advent of modern medical technology (e.g. ultrasound), we couldn't predict the gender of any individual child, yet throughout human history we've more or less had the same ratio of males to females born.

  2. For similar reasons, I think theological determinism exhibits all the randomness of a lottery. The lottery may accomplish or further divine objectives, but it is conducted randomly. It's thoroughly deterministic, but it remains random.