You can certainly shave dry or with oil - and I have done it - but there is no doubt at all that you will get an easier, more comfortable, and closer shave if you use water to soak the beard before shaving. The difference will be obvious, and soaking the beard for longer is better. When I soak my beard for a good 5-10 minutes in the shower, or have a long bath, I consistently get the best shaves and can get great closeness even with mild razors.
I don’t think there can be any factual debate about this. An easy experiment to demonstrate it is to cut your fingernails after soaking one hand for 5-10 minutes and keeping the other hand dry. It is a night and day difference how much softer your nails are when soaked, and hair and fingernails are the exact same material (keratin).
I don’t think there can be any factual debate about this. An easy experiment to demonstrate it is to cut your fingernails after soaking one hand for 5-10 minutes and keeping the other hand dry. It is a night and day difference how much softer your nails are when soaked, and hair and fingernails are the exact same material (keratin).