Post History

Let's look at the described phenomena, as they changed over the years.

First we have ownership: the idea that a particular person has a right to determine what is done and not done with a physical object. An owner worries over their property: is this carved stick still with me? They care about it. In order to relieve their frustration, they do something to the physical object that makes it less likely to be taken: they tie it to their belt. Now they are free(r) from caring about the stick, the stick is secure and it has been secured by the loop of string.

Now the owner loans the stick to a neighbor. How can they be sure it will be returned? A long string is impractical. Instead, the neighbor leaves behind a painted rock: as long as the stick is gone, the rock remains, providing security for the neighbor's good behavior. And if the stick does not return, the agreement is that the rock is now the property of the stick's owner.

Investopedia is a good resource here:

https://www.investopedia.com/terms/s/security.asp

"The term "security" refers to a fungible, negotiable financial instrument that holds some type of monetary value. It represents an ownership position in a publicly-traded corporation via stock; a creditor relationship with a governmental body or a corporation represented by owning that entity's bond; or rights to ownership as represented by an option."

An instrument means that it is an agreement, just like the one that governs the rock-string relationship. "Negotiable" means that it is subject to exchange: it can be traded for a painted rock, and then the ownership of the carved stick is traded in return. "Fungible" is, perhaps, the most interesting part: it is one of many that are so like it, any of them are perfect substitutes for the others. There is no personal attachment to this painted rock or this carved stick, because there are many carved sticks that are so exactly alike we only care that the right number are exchanged, not for which particular sticks they are. 

There are agreements which are not fungible but can be negotiated: the ownership of a unique sculpture, for instance. We care a lot about the particular sculpture, so we will make arrangements to reduce our worries -- security. 

There are agreements which are not negotiable: a will establishes ownership of parts of an estate, and though the parts can be traded later, the will itself is not an agreement that one can sell.

So, security is the amelioration for worries over ownership, and it can mean anything on this spectrum:

- actions taken to protect an object

- items to hold hostage against the return of your own object

- agreements to exchange hostage objects

- agreements that represent ownership of immaterial objects (equity) or valid debts (bonds), so that these documents can be traded

Does that help?