What is the minimal amount of information necessary to identify any one individual?

I was recently reading a book by Laureen R. Jaussi [Jaussi, Laureen Richardson. Genealogy Fundamentals. Orem, Utah (284 East 400 South, Orem 84058): Jaussi Publications, 1994]. She list the "six elements that uniquely identify individuals" as the following:

• Names
• Places
• Dates
• Relationships
• Occupations
• Gender

I have commonly expressed the opinion that any individual can be identified by only three of these: name, date and place. This entry got me thinking about whether I needed to be a little more specific and whether or not what I had been saying was not completely correct. My thoughts then expanded to include the concept of the universal family tree, where each individual occupied only one node on the tree. What does it take to define the node and thereby define the individual? 

I think an argument can be made to include even more criteria for defining the existence of an individual such as birth order (which may be included in relationships). After some consideration, I believe there are really two different questions involved here, first the question of the existence of the person and second the question of differentiating the person from others with the same or similar identifying elements. 

My concept of the human family tree is relatively simple. In can be stated as the following rule:

Every person who ever lived or will live on the earth has a unique set of biological parents coupled with a unique birth order. 

Even identical twins (triplets etc.) have a unique birth order. Disregarding societal and cultural adaptations, everyone has only one biological father and one biological mother. So no two people can occupy the same node at the same time. I define the term "node" to mean the conjunction of the relationship between the parents that produces a child. The simplest representation of this relationship is the commonly used pedigree chart. 

Why is it important to view the human family as a lattice work of unique nodes? Because any other considerations obscure the fixed physically defined relationships between the individuals. But it is obvious that the "tree" created is not simple, but complex. One parent can (and commonly does) have children in different relationships, i.e. out-of-wedlock, divorce, death etc. Notwithstanding the societal or cultural changes or multiple relationships, each of the children produced has only one biological father and one biological mother. Thinking of the relationships in this way illustrates the uniqueness of the individual and makes identification of any individual possible since there is no danger that two people can physically occupy the same node on the human family tree.

But from the perspective of genealogy, that is, trying to identify the individuals in the human family tree and assign them each a position, it would have been much easier to simply record each birth as it occurred. The human family tree would have then been completely defined. We all know this did not happen, so we are in the position of trying to discover those who occupy each node from the bottom up rather than from the top down. Due to lack of record keeping, in actual practice, both directions of investigation become very difficult.

Back to the initial question, what is the minimal set of criteria that will adequately define an individual in the human family tree? You might notice that I added the qualifier "adequately." This is a concession to the contextual issues raised by the lack of complete documentation. 

Now, after more consideration, I am still of the opinion that there are only three facts needed. I will call these a name, a date and a place. The one that needs to be more fully explained is the place. I consider the place to be defined as "the exact location of a verifiable event in the life of the person." 

So, from my perspective, trying to identify someone merely by giving a name, with an approximate date and a general place is not sufficient to adequately define the person for inclusion in any specific node on the human family tree. Of the three, names are the least important. A baby can be born and die without a name and the exact date may be impossible to determine, but the place has to be exact or there is always the possibility that the person has not be adequately identified. 

Obviously, my approach calls into question huge segments of what passes for genealogy today. You can look at any extended pedigree and find people listed by name only with a vague reference to a date and no place. We can always conclude that any person had two biological parents. So those genealogists who simply avoid this issue by assigning the parents the names of Mr. and Mrs. are improperly avoiding the issue. We know they exist, the trick is documenting their existence. 

Why do I reject gender, relationships and occupations? Because all these are secondary considerations involving proof not central to the identification of the individual. All three of these may be unknown and yet the person can still be adequately identified as occupying a unique node. The only relationship necessary for identification is the biological relationship to a single mother and a single father. 

This brings me back to my first rule of genealogy: if the baby was born, the mother was there. Hence the three things needed to identify this person. 

Now, back to the two questions I mentioned above. The first is the question of biological identity. The second is the question of historical context. Positive proof of the first question usually, but not always, determines the second question. I concede that additional information may be necessary to adequately differentiate two individuals with similar basic facts.