Is it sensible to think that time is more fundamental than space, because one can just close one's eyes and relive memories, going back in time or prospectively go forward in time to predict something, without actually changing your position in space?

One can think about different times, but one can also think about different places; and although one can not choose when to be, one can choose where to go.

Our experience of objects (including ourselves) in space and time seems vital to our human existence, and I'm not sure what it would mean to say that either spatiality or temporality is more important than the other.

Since thinking about events that may have happened in the past or events is not literally time travel, so spatiality seems to "beat" temporality with respect to ease of travel, which your question refers to. The difficulty of self-directed travel through time doesn't mean that temporality is unimportant, however.

The thesis that time is more fundamental than space is not uncommon among philosophers -- although the significance attached to this, and the meaning of 'fundamental' varies widely. At least arguably, Aristotle, Leibniz, Kant and Heidegger, are committed to some variety of this claim.

Kant's argument has some similarities to yours. All propositions about things and events must, when fully analysed, include a subordinate proposition about time (if only the location in time of the act of thought itself). But not all propositions about things and events must include a subordinate proposition about space. Kant then uses this analysis to argue further that the basic categories of all thought must be understood to be rules for the determination of time relations.

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