Dumb question about water intake

I know this place says 8 glasses per day. But here's a better equation to determine your daily intake.

Take your weight and divide it by two. This number is how many ounces of water you should drink.

Like me, I weigh 168. 168/2= 84. I should drink 84 ounces per water a day. That's 10.5 glasses compared to the recommended 8. Like everything else your intake should be dictated by you and your size, not universally for everyone.

I know this place says 8 glasses per day. But here's a better equation to determine your daily intake.

Take your weight and divide it by two. This number is how many ounces of water you should drink.

Like me, I weigh 168. 168/2= 84. I should drink 84 ounces per water a day. That's 10.5 glasses compared to the recommended 8. Like everything else your intake should be dictated by you and your size, not universally for everyone.

A suitable allowance of water for adults is 2.5 liters daily in most instances. An ordinary standard for diverse persons is 1 milliliter for each calorie of food. MOST OF THIS QUANTITY IS CONTAINED IN PREPARED FOODS".

Dr. Valtin believes this last sentence may have been ignored, leaving the incorrect interpretation of these early dietary guidelines that eight glasses of water to be drunk each day.

64ozs a day is suggested. So, yeah that would make your cup 8ozs.

By who? With what proof?

We need less than we think. Among most adults, he found, caffeinated and alcoholic beverages constitute half or slightly more of their daily fluid intake, meaning the average adult drinks a respectable 1,700 ml and this doesn’t include the water from foods and metabolism, which also count. Yet, the medical research indicates that even 1,700 ml may be as much as a full liter more than what sedentary adults actually need to maintain physiological homeostasis, he said.

He couldn’t find any article where 8x8 was recommended on the basis of scientific evidence. The idea seemed to appear out of nowhere. He did, however, find one possible source for a misinterpretation that may have been repeated, like urban legends often are. The 1945 Food and Nutrition Board of the National Academy of Sciences had written in its Recommended Dietary Allowances:

A suitable allowance of water for adults is 2.5 liters daily in most instances. An ordinary standard for diverse persons is 1 milliliter for each calorie of food. Most of this quantity is contained in prepared foods.
Dr. Valtin believes this last sentence may have been ignored, leaving the incorrect interpretation of these early dietary guidelines that eight glasses of water to be drunk each day.

It was emphasized that the findings in the study are limited to healthy adults in a temperate climate leading a largely sedentary existence. It seems to me that leading a largely sedentary existence would not allow for good health in an adult. Therefore, the foundation of the study draws a mythical conclusion at best.

I have come across this level of ignorance about the primary physiological role of water at another Ivy League medical school from another eminent professor of physiology who, like Dr. Valtin, researched and taught the water-regulatory mechanisms of the kidney to medical students and doctors. Only when I asked him what “hydrolysis” is, did the penny drop and he admitted the scientific fact that water is a nutrient and does indeed possess a dominant metabolic role in all physiological functions of the body.