zombiess
10 MW
I haven't seen this exact explanation yet after some quick searching. Thought I would share it here as it's been rattling around in my head for a few days since I thought it up. I doubt I'm the first as it seems pretty obvious 
I've often heard older people make expressions such as "youth is wasted on the young", "you'll be old before you know it" and "blink and next thing you know your 70". As a child, understanding these concepts is near possible, you may only have knowledge of it. That knowledge only becomes understanding with experience.
A consciousness experiences the passage of time whether it is considered to exist (classical physics) or does not exist (quantum mechanics).
When a persons consciousness comes into existence, it does not understand the concept of time, that only comes with experience. When born, a person has only experienced the world for a few minutes. Those minutes could seem like an eternity as there is no concept of what a minute is as there is no reference point. As the person ages, each successive day starts to make up a smaller and smaller part of the consciousness's experience. At 1 year a day makes up 1/365th of the experience. At 10 years, 1/3650th, or 1/10th of what it was at 1yr old. At 30yrs old a day is ~1/10950th of the life experience. Make it to 70yrs old and a single day is just 1/25,550th of the conscious life experience. As you can clearly see, each day is "worth" less than the previous. Our brains are adaptive, so they tend to tune out that which is already known and dismiss it. As experience grows, there is less to experience.
I believe those who are older and still keep current with technology and current events will continue to have "young minds" as they age. I believe feeling young mentally is all in exercising our ability to learn and becoming excited about new things.
*edit* I forgot to add this part.
Since we say that time is a constant rate, shortening up each day using a 1/x formula leads us to smaller and smaller pieces with each day. Since time is constant, it now goes through each of those days at what appears to be a faster rate to our consciousness. This gives us the illusion that time is passing by faster.
It's a lot like a long road trip, the first time seems to take long. The trip back is often shorter since you have already experienced the surroundings. The next trip often goes by even quicker since you know the landmarks.
I've often heard older people make expressions such as "youth is wasted on the young", "you'll be old before you know it" and "blink and next thing you know your 70". As a child, understanding these concepts is near possible, you may only have knowledge of it. That knowledge only becomes understanding with experience.
A consciousness experiences the passage of time whether it is considered to exist (classical physics) or does not exist (quantum mechanics).
When a persons consciousness comes into existence, it does not understand the concept of time, that only comes with experience. When born, a person has only experienced the world for a few minutes. Those minutes could seem like an eternity as there is no concept of what a minute is as there is no reference point. As the person ages, each successive day starts to make up a smaller and smaller part of the consciousness's experience. At 1 year a day makes up 1/365th of the experience. At 10 years, 1/3650th, or 1/10th of what it was at 1yr old. At 30yrs old a day is ~1/10950th of the life experience. Make it to 70yrs old and a single day is just 1/25,550th of the conscious life experience. As you can clearly see, each day is "worth" less than the previous. Our brains are adaptive, so they tend to tune out that which is already known and dismiss it. As experience grows, there is less to experience.
I believe those who are older and still keep current with technology and current events will continue to have "young minds" as they age. I believe feeling young mentally is all in exercising our ability to learn and becoming excited about new things.
*edit* I forgot to add this part.
Since we say that time is a constant rate, shortening up each day using a 1/x formula leads us to smaller and smaller pieces with each day. Since time is constant, it now goes through each of those days at what appears to be a faster rate to our consciousness. This gives us the illusion that time is passing by faster.
It's a lot like a long road trip, the first time seems to take long. The trip back is often shorter since you have already experienced the surroundings. The next trip often goes by even quicker since you know the landmarks.
