“Many kinds of experiments are repeatable after all.”
Only very simple ones, and even then “same” must be interpreted loosely. Pick up a ball. Drop it from a given height onto a specified surface. How high will it bounce? There is no error term in the laws of motion, but the actual result will vary considerably because of all the variables—spin axes, wind, the temperature of the ball and surface—that you aren’t controlling for. Most “interesting” results scientists (from physicists to sociologists) get turn out to be unrepeatable—sometimes they are artifacts of a measuring apparatus, but sometimes they’re caused by something as simple and impossible to remember o determine as “that time I stirred counterclockwise.” This is especially true in biology and medicine (see http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1182327/ and http://www.theatlantic.com/magazine/archive/2010/11/lies-damned-lies-and-medical-science/308269/).
Yes, experiments at the frontier of science are often unrepeatable, but that’s just a selection effect, no? Those problems are interesting precisely because we have not nailed down all the cause-and-effect relationships yet. An enormous number of cause-and-effect rules are so well understood that they are not considered scientifically interesting anymore, and it is those rules that allow us to navigate the world, get to places on time, stay out of mortal danger, and so on. Of course there is random error as you say, but the error is not infinitely large.
Anyway, I keep picking this nit because the Russel quote says that our causal models of the world are not just imperfect but actually “obsolete and misleading,” which sounds like an exaggeration.
Maybe he means something along the lines of same cause, same effect is just a placeholder for as long as all the things which matter stay the same, you get the same effect. After all, some things, such as time since the man invented fire and position relative to Neptune and so on and so forth cannot possibly be the same for two different events. And this in turn sort of means things which matter → same effect is a circular definition. Maybe he means to say that the law of causality is not the actually useful principle for making predictions, while there are indeed repeatable experiments and useful predictions to be made.
“Many kinds of experiments are repeatable after all.”
Only very simple ones, and even then “same” must be interpreted loosely. Pick up a ball. Drop it from a given height onto a specified surface. How high will it bounce? There is no error term in the laws of motion, but the actual result will vary considerably because of all the variables—spin axes, wind, the temperature of the ball and surface—that you aren’t controlling for. Most “interesting” results scientists (from physicists to sociologists) get turn out to be unrepeatable—sometimes they are artifacts of a measuring apparatus, but sometimes they’re caused by something as simple and impossible to remember o determine as “that time I stirred counterclockwise.” This is especially true in biology and medicine (see http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1182327/ and http://www.theatlantic.com/magazine/archive/2010/11/lies-damned-lies-and-medical-science/308269/).
Yes, experiments at the frontier of science are often unrepeatable, but that’s just a selection effect, no? Those problems are interesting precisely because we have not nailed down all the cause-and-effect relationships yet. An enormous number of cause-and-effect rules are so well understood that they are not considered scientifically interesting anymore, and it is those rules that allow us to navigate the world, get to places on time, stay out of mortal danger, and so on. Of course there is random error as you say, but the error is not infinitely large.
Anyway, I keep picking this nit because the Russel quote says that our causal models of the world are not just imperfect but actually “obsolete and misleading,” which sounds like an exaggeration.
Maybe he means something along the lines of same cause, same effect is just a placeholder for as long as all the things which matter stay the same, you get the same effect. After all, some things, such as time since the man invented fire and position relative to Neptune and so on and so forth cannot possibly be the same for two different events. And this in turn sort of means things which matter → same effect is a circular definition. Maybe he means to say that the law of causality is not the actually useful principle for making predictions, while there are indeed repeatable experiments and useful predictions to be made.
Hmm. Yeah, that makes sense. (And very nicely put!)