Doubt yourself and you doubt everything you see. Judge yourself and you see judges everywhere. But if you listen to the sound of your own voice, you can rise above doubt and judgment. And you can see forever.
There is no doubt that we should take solar radiation into account. We have seen ground temperatures rising since 1975, and it is important to know to what extent that has been caused by the sun or by carbon dioxide.
I know that we're being inexorably taken over by the Americans. Without a doubt. I don't mean invaded or anything like that, just taken over. By degrees.
In these times, the hardest task for social or political activists is to find a way to get people to wonder again about what we all believe is true. The challenge is to sow doubt.
Melancholy and sadness are the start of doubt... doubt is the beginning of despair; despair is the cruel beginning of the differing degrees of wickedness.
There is no doubt that I, also, had long been aware of the problem, i.e. producing X-ray interferences, before the inherent difficulties had finally been surmounted.
Indeed, I am sometimes inclined to doubt whether some men consider youth as rational and intelligent beings, with minds capable of expansion, and talents formed for usefulness.
