...in other words, the soul of The First Man, Adam, contained within it the souls of all future generations to come.
Hence, All of Our Souls, are dervied from Adam's "Super Soul".
The process of "re-incarnation" then, can really be considered a process from which the First "incarnation" is first "derived" from The Greater Soul (G-D to the First Man Adam, then from him, through all the generations before us) and then the individual soul permutaion that is You, me, is "created, imaged & instantiated" or "forked", "branched", ("Tree of Life") (for the purpose of scaling Humans (Bnei Adam, Sons of Adam) to the capacity required to sustain a Perfect Messianic World) like a partical of a soul from souls that came before, going all the way back, and originating in the First Soul of Adam and then...to You.
...in this method souls "multiply" from one to many...
building the incremental knowledge required. This is The Order of Development | Seder Hishtalshelut.
גלגול הנשמות
The words for Re-Incarnation of Souls in Hebrew is "Gilgul Neshamot", which means "Loop of The Souls", and a loop, by definition is Infinite.
In a Loop, the end is tied with the begining to create Infinity. This is the secret within Circles, as any point on the loop / circle, can be the end or the begining. (It is also the solution to the problem of Pi...but that one is for another time)
When we die, we are judged, and depending on the Mizvot, Good Deeds, of our current Incarnation (Life), we then get a chance to step into "The Gate of ReIncarnations" to "Step Back into The Loop of Souls" to come again, and be Re-Incarnated as a part within the Soul that is coming now to be Incarnated...and in this process, all the "old" souls also mix with the new souls, but all originally coming from that One Super Soul.
...and in this way, through G-D's Mercy, we are given the chance to come to this world...the first time, and the times that come after, to come to fix & enhance...
...so...
We cannot remember these Other / Past Re-incarnations, because they are hidden in our Soul's makeup.
They are Lives of others, and they are many...what is important is THIS Instance, our current Life.
Our soul, contains within it new hope, purpose, missions, destiny, to create new positive memories, built on top of previous mistakes within our history. Tikkun.
...mind bending, i know...think about it, meditate on it...it will make sense Be"H...