What is the age of the Earth if time does not exist?
Answer by Peter Jones
If time does not exist then the Earth has no age so the question is odd as stated, but I know what you mean.
To make sense of the metaphysical non-existence of time, the idea that time is reducible, it is necessary to view the psycho-physical world as an aspect of Reality, the other aspect being unmanifest, timeless and placeless.
This double-aspect approach is explained and discussed at length by Hermann Weyl in hie writings on the continuum. He points out that we do not experience the passing of time but create it as a theory. This leads to a dual-aspect approach for which time is contingent, albeit real enough in everyday life. This is the orthodox approach in the Perennial tradition and so we we see, for instance, that Meister Eckhart warns us against becoming too involved with time since it is not truly real. The Buddhist sage Nagarjuna proves this and gives us his dual-aspect doctrine of ‘Two Truths’ for which nothing is really real. If you look around you’ll see that nobody who ‘reifies’ time as a fundamental phenomenon can make sense of it.
To reduce time we have to reduce all time-based phenomena. Thus your question is muddled. It reifies the planet Earth but rejects the reality of time. But time and time-based phenomena have to be reduced all together or not at all. The doctrine that time is not really real requires that the Earth is not really real along with its multifarious inhabitants.
Thus for the conventional or naively-real aspect the age of the Earth is a few billion years, while for an ultimate view or ‘metaphysically’ it has no age or true existence. Note that the idea is not that time does not exist but, rather, that existence is not what we usually think it is, such that time does not ‘really’ or truly exist as any more than a conceptual phenomenon . Kant may also be worth a read on this topic.
A dual-aspect approach is vital since the extreme idea that time does not exist is clearly nonsense. Time clearly exists in a sense and the question is only in what sense. All this is explained in the literature of the Perennial tradition.