While philosophers and religious thinkers have taken past lives seriously, it is usually assumed that serious scientists are happy to leave them to it. But the University of Virginia School of Medicine has applied the scientific method to this matter and has found interesting evidence that cannot be dismissed out of hand. Recently, the Washington Post did a thoughtful piece on this subject, looking at the evidence in a critical but balanced manner.

The method of testing the possibility of a past life, or at least the possession of memories from before a person was born goes back at least to Socrates. In the Meno, Socrates endeavors to argue for his doctrine of recollection. He claims that knowledge of such things as geometry and the Forms are acquired by the soul before it is embodied. People forget that they have this knowledge, but it can be restored by philosophical discussion. This, as I tell my students, can be seen as like losing files on your PC due to some corruption and then restoring them with a utility.

In the dialogue, Socrates walks Meno’s slave through a geometric exercise Because, according to Socrates, the slave did not learn geometry in this life, he must have learned it before he was born—while his soul was communing with the forms.

This, then, is the test for past lives: if a person has knowledge of a past life that they could not have acquired in this life, then that counts as evidence for a past life. Other factors, such as behavioral changes, can also serve as evidence. The Washington Post article does provide examples of cases that seem to provide evidence of such knowledge and behavior. Perhaps the best-known case is that of James Leininger. Dr. Jim Tucker provides a detailed analysis of the evidence and considers alternative explanations.

Going back to Socrates, critics respond to his argument by claiming he guided the slave through the exercise and is thus supplying the knowledge in a way that does not require any prior existence. The same concern applies to evidence of past lives: a person could be asked leading or guiding questions that make it appear that they have such knowledge. This is not to accuse people of deceit; this could happen without any such intention. But, of course, fraud is also a matter of concern. The credible investigations consider both these possibilities, and they should be given due consideration. As Hume said about miracles, we know that people lie and that can often be the most plausible explanation. Less harshly, we also know that people can unintentionally ask leading and guiding questions while we don’t know if people have past lives. So that explanation is, by default, the favored explanation until it is overturned.

Another obvious concern is that with the internet, a child could learn information that they present in a way that might seem like they are recalling a past life. Children also often pretend they are other people, be it a type of person or a specific person. The challenge is determining whether the child could have plausibly found the information and whether the behavior that seems to indicate a different personality is a matter of play or something else. By Occam’s Razor, the explanations that do not require metaphysical commitments have an initial advantage. But there are certainly metaphysical matters to consider.

Socrates presents what could be considered the standard version of reincarnation: a person is a soul, and the soul has a means of storing memories across lives. When a soul is reborn, it (might) recall some of these memories. While Socrates focused on things like the Forms, these could be mundane memories from a past life. As there are many competing accounts of the metaphysics of personhood, memory, and identity, these would all need to be considered and assessed. For example, Hume dispenses with the soul in favor of the idea that the self is a bundle of perceptions (before he concludes this matter is just a dispute over grammar). Memories are just stored perceptions, and these presumably could end up being part of a new person (or a continuation of the old).

John Locke explicitly talks about consciousness persisting or not doing so, so his theory would allow for the possibility of reincarnation. Buddhism also has a metaphysics that allows for reincarnation, albeit in a way that involves no self.

Interestingly, Dr. Tucker’s paper presents “thought bundles” or “thought pools” as possible explanations of these past life memories. The idea is that a living person connects to these bundles or pools and somehow taps the information in them. In terms of a metaphysical foundation, these could be Hume’s bundles or perhaps the remnants of a Lockean consciousness. These bundles or pools do raise many questions, such as what they are, how they would persist and how a person would access them. That said, the human brain is a known storage system for such information, and we routinely transfer information—you are experiencing this right now as you read this. But due skepticism is wise here and the idea of thought bundles existing like lost smartphones and being accessed by a mental 5G is one that should only be accepted based on adequate evidence. After all, this would seem to require that people have a form of psionics that allows them to access such information. While not impossible, since we know information can be transmitted, there does not seem to be much credible evidence for this.

In closing, as there is some credible evidence of this sort of special knowledge and metaphysical theories advanced by philosophers that would allow past lives, then this matter is worthy of due consideration.