Subject: Is pH a physical or chemical property?

I read in your archive that pH is a physical property, but I'm still confused 
as to why.  It would seem to be a chemical property, since it relates to how 
the compound will react.  The only thing I can come up with is that by 
definition, a physical property can be measured without altering the 
substance.  This seems to work with pH meters, but not with indicators?

Re: Is pH a physical or chemical property?