Hiking alone is like any other experience that carries some measure of danger, one must do a little risk mitigation analysis.

List the obvious risks.

Apply a value to each. (breaking a leg carries a higher value than turning an ankle, as an example)

Assign a probability to each (meteor shower is less likely than a rain shower)

Multiply the risk value by the probability and you'll get a list of risks in a rank order of impact. You just need to mitigate those risks through training, equipment, practice, etc.

If you can mitigate the negative potential of the risk to the point of being comfortable for you, go for it.

There's no universal answer, of coure. But it will make you think ahead of time before you venture out. My guess is that the experienced solo hiker has done this sort of analysis, perhaps not even know that he or she was doing it.