If it is an irrevocable law of physics that energy cannot be created out of nothing, then it is also irrevocable that money cannot be created out of thin air.
Money is "stored energy" - it stores work. When you spend money you unlock energy, e.g. the work that went into making the candy or clothes or whatever, for which you exchange the money. So when you simply print money with no reference to any work done, the energy that is stored in all the “good”money that was created with reference to work will have to spread out to cover the “bad” money that was simply printed with no reference to work, thus devaluing the “good” money.
To use a metaphor: If you turn one bottle of whisky into two bottles by watering it down, the whisky that you then will have will not be as potent (energised with alcohol) as the whisky you had in the original bottle of undiluted whisky. While you may have two bottles of whisky, you will have to drink twice as many shots to get the same level of inebriation achieved before you watered the whisky down.
If you were to buy this watered down whisky in a bar, you would be paying twice as much to get the same level of inebriation that you got when you were served whisky that had not been watered down. In other words: the same amount of money now only buys you half the pleasure (if inebriation is your pleasure). Subsititute “pleasure” with “standard of living” and you get my point. You will be paying twice as much to maintain your standard of living (getting as drunk as before) or you will be spending the same amount as you used to spend, but you will be living at half your previous standard (leaving the bar half as drunk).
This would not be a problem if your income doubled every time the purity of the whisky was halved. Yes, you would eventually need a very large wallet, even a wheelbarrow, to carry the cash needed to pay for your whisky, but at least you would still leave the bar as drunk as before. But, and this is a big but: Will your income double each time the purity of the whisky is halved? Ay, there’s the rub.
Economists argue extensively about the why’s, the if’s, the how’s and the when’s regarding the relationship between income and cost of living. But ask yourself this: Does it feel like your salary is keeping pace with the cost of living? If your answer is yes, then you are as happily inebriated as you were before; if no, then you might want to consider to what levels of sobriety all the money that the central banks of the largest economies in the world are printing will drive you in the coming years.