Live Blogging: Pitts

Question about connection with observables and diffeomorphisms. Replies never used diff talk. Rejects invariance in favor of covariance. See Trautmann: need actual points, and never move them alone, only individuated by fields. 

Is main idea that we introduce points? No. Doesn’t introduce them primitively. Thinks active diffs don’t make much sense: like building a building, seeing you don’t need it, and knocking it down.

Accused of adding points and having more information. Responds that you only get them after the fact. But what if have two manifolds? Why? Question continues: moving points around gives same physical situation. Pitts: we all agree that points exist in GR, just not individuated until have the metric.

This was a confusing QA session. Not sure what the actual worry of the questions was. Butterfield tries to redirect from point type worries to the actual issue of whether we need to coordinate the constraints in order to generate gauge transformations. 

I could not really follow Dittrich’s point. If anyone is reading this, perhaps that can be filled in here.

Argument at length about the connection between phase space and observables generally. Chair cut it off.


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s