“If simple observation were the only factor in determining our knowledge of reality, then nothing at all can be more certain than the fact that the Earth is stationary. For thousands of years humankind has observed the turning of the stars and (apart from the odd earthquake) has experienced the ground beneath its feet as a fixed point from which to observe all other movement. ...“
*source; (first published in UK 2001 by Hodder Education)
I assume the ‘were’ implies the 2nd conditional and the ‘can’ does the 1st conditional(indicative mood). However, I can’t understand how such a combination - the 2nd conditional mixed with indicative mood - is possible at all. In my opinion the ‘can’ above should read ‘could’. Or the recent grammar rule for subjunctive is maybe changing to the extend which allows upto ‘can’?Your valuable opinions would be much appreciated.