According to most spiritual texts it is our present or now moment that creates our future - Eckhart Tolle's book is a prime example, even in the title... The Power of Now. So I would have to say that it is our present that is the foundation of our future.

With regards to the past, I think the best we can do is learn from it, which often leads to a change in perception allowing us to let go of a lot of those past memories that have been keeping us stuck. This in turn allows us to live more in that present moment where true power resides.

As for proof, we don't need it.... all we need is faith and what begins to show up will be a corroboration of that faith and no further proof is needed.

In order for a dream to come true, it must be dreamt, for a goal to be accomplished it must be set, and for a prayer to be answered it must be asked, before a word is spoken it is a thought, cause and effect this is the proof. Today is the manifestation of our previous thoughts and desires. Sometimes it is the lack that we have manifested, but it is still our manifestation. Today's thoughts, dreams and desires are the foundation of our future.

I read George Orwells Nineteen Eighty-Four in the late 70ies and a quote that stuck with me from it was "He who controls the present, controls the past. He who controls the past, controls the future." So as stated before now is the foundation for the future. Yesterday might give you some inspiration on your tomorrow but it is today you decide and take action.
peace

The present is the foundation of the past. And the future is the foundation of the present.