Thursday, February 9, 2012

Are the laws necessary?

We've been wrestling with a variety of interesting issues associated with laws of nature in my Metaphysics and Epistemology class. For those of you that are interested in reading more about the topic, the Internet Encyclopedia of Philosophy has a fairly good entry. The entry in the Stanford Encyclopedia of Philosophy is more thorough. Section 8 of the latter has a very concise blurb on the material we discussed today having to do with necessitarianism and the references throughout the entry will be very useful if you're working on a paper related to laws.

Of special note in the SEP entry is the following passage:

"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 Fs are Gs 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. They also appeal to Saul Kripke's (1972) arguments meant to reveal certain a posteriori necessary truths in order to argue that the a-posteriori nature of some laws does not prevent their lawhood from requiring a necessary connection between properties. 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., Bird 2005, 356). 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 1982, 209; Fales 1990, 85–87)."

So necessitarians might defend their position by claiming: (a) conceivability does not entail possibility and/or (b) the a posteriori nature of some laws does not prevent their lawhood from requiring a necessary connection between properties. You might consider writing one of your short papers on one of these attempts at defending necessitarianism.

Here might be a good place to air some ideas about these two lines of defense. Comments about (a) or (b) are welcome.


Jacob Shepherd said...

It seems to me that, with (a), necessitarians might need to clarify what they mean by "conceivability" and "possibility". Is it possible for me to be moving and stationary at the same time? I think the anti-necessitarian would say "no" because I can't conceive of that -- it's impossible to imagine something moving and staying put at the same time. But aren't I conceiving of it because I just mentioned it, and so something of the image of it is in my head?

This would not entail possibility, though. I think the necessitarian would say, like me, that you can imagine something exploding and imploding at the same time, but that doesn't mean it's possible. Likewise, we could imagine what it would be like if it were a beautiful summer day and there was a snowstorm happening. It seems like in the craziest fantasy of ours that the snowflakes could be just "appearing" from another dimension (or something) and making it snow when it's 80 degrees out. OK, maybe under that condition it's possible.

Scratch the other dimension part then. That would be a case in which conceivability would entail possibility.

The snowflakes are falling, then, without coming through the other dimension. It's conceivable (unless I'm wrong), but it's not possible because of the laws of nature. In no possible world could it be snowing and sunny at the same time, because the laws of nature just can't be happening in such a way as to allow that.

I'm doing my best here....

Jesse Steinberg said...

Jacob, You bring up an interesting issue about conceivability. What does it mean exactly to say that something is conceivable? You start with something like: If one expresses or characterizes some state of affairs, then that the state of affairs is conceivable. I wonder if that's enough. I can say "square circle" but this doesn't seem to entail that I have conceived of a shape that is both square and circular. Simply writing something down or speaking certain words isn't enough for having a (robust) conception of something.

What more is needed? We might start by thinking about what it is to FULLY IMAGINE something. The barber paradox is mentioned in a "Friday Paradox" post a few weeks ago. I think this is an interesting case that has a lot to do with the issue we're discussing here. The barber MIGHT appear to be conceivable (e.g., I can imagine a barber having various properties). But I can't seem to imagine a barber that has the peculiar property that makes for the paradox--the property of shaving all and only those individuals that don't shave themselves. Similarly, I don't think I can imagine something exploding and imploding simultaneously. I can't fashion a "mental picture" of such thing. But maybe this isn't what it is to conceive of something. If it's not, then what is it to conceive of something?

As you suggest, it will be helpful to think more about these cases to get a little clearer about what philosophers mean by 'conceivable.' And this topic would be great for a paper! There's quite a bit written on this topic. Let me know if you need some suggestions of where to start.

Jacob Shepherd said...

Thank you, Jesse. This is a great issue that I've been thinking about for a little while now in small bit of length.

I think I'd be ready to admit that we cannot conceive of contradictory mental images, such as an imploding and exploding object, by the definition I think you are using. That is, by way of forming "mental images" of them (if I understand you right). But I think you are trying to imagine a concept that you want to be "real" in the imaginary sense (i.e., something that is cohesive and metaphysically possible). If it is metaphysically impossible, it cannot be imagined, you say. But I don't know for sure what to say about that (...yet, hopefully). I feel like conceiving does not mean imagining "real" concepts. I feel that all conception requires is putting concepts together, whether they are metaphysically possible or not.

Before talking more about something I don't know much about, though, I should probably consult you and some literature. I feel like I may be sounding a bit like an airhead. Thanks again!

Anonymous said...

Our idea of motion is inconceivable without reference to some other object. An object cannot be at both point a (stationary) and b (in motion) with respect to some other object as this would the defy the lone principle that something cannot both be and not be. Moreover, how does one embrace a particle that is, presumably, also a wave, yet toss conceivable as possible?