—XKCD
A popular scientific observation is that all of the atoms in our bodies are in constant transition. They are shed from our bodies at a constant rate, with new atoms taking their place. The atoms that form your brain are replaced about every twelve months and almost your entire body is replaced about every seven years.
Therefore, how can you say you are the same person that you were a year ago? You can, of course, because your subjective consciousness is not a physical entity, it is an intangible system that is supported, but not reliant on, a physical substrate.
As with any system, it is maintained by a physical substrate, in this case your biological brain. The components of the system may change, but the system itself remains consistent.
Similarly, a computer system can be copied from a magnetically-encoded hard drive to an electronically-encoded RAM chip whilst maintaining its integrity.
If the carbon-based biology of your conciousness is constantly changing without your mind collapsing, then why couldn’t your mind be transferred to a silicone-based substrate, such as a computer processor?
The truth is that it doesn’t matter what form your mind takes, as long as its structure is maintained. This leads us to the inevitable conclusion that our minds may one day be copied onto a computer and that this copy would itself be an individual sentient mind.
As uncomfortable as it may make some people feel, there is no evidence to support the notion that our human consciousnesses are inextricably linked to the biological packages of meat, bone and grey matter that house them.
I believe that the concept of a “soul” has been created as a means to escape existential confusion and fear but remains unsupported by evidence or reason.
Rather, what we are left with is conciousness; a complex system which is reliant upon, but not restricted to, a particular physical substrate.
If you take the chemicals that create the emotion of love and combine them on a petri dish then have you created love itself? Most people would say that you haven’t, but when this exact reaction occurs within a human brain an emotion is said to have occurred.
Scientists can describe the physical properties of a single human thought by recording the electrical and chemical activity in the brain, yet what they are mapping is simply matter and energy moving through space, it is not the thought as experienced by the thinker. The qualia is “lost in translation”.
There is a gulf between the dimensions of objective facts from subjective experience. The two can influence each other, but between them is a fundamental divide.
As an example, the fundamental laws of logic hold true whether there is anyone around to define them as true, yet it takes a mind to conceive of those laws and of the concept of truth.
“…this world known as the First Sirian Bank is a planet with a… crust consisting almost entirely of crystalline silicon… over the billenia earthquakes and so forth have caused the formation of billions of transistor junctions within that crust, forming by natural means the largest computer in the galaxy… we find the First Sirian Bank not only alive, but possessed of a universe-view sufficiently advanced to call him Human.”