J. D. Bernal (1901–1971)

mechanical details, it appears that the most effective method is based on the principle of the rocket, and the difficulty, as it exists, is simply that of projecting the particles, whose recoil is being utilized, with the greatest possible velocity, so that to economize both energy and the amount of matter required for propulsion.

...form of space sailing might be developed which used the repulsive effect of the sun's rays instead of wind. A space vessel spreading its large, metallic wings, acres in extent, to the full, might be blown to the limit of Neptune's orbit.

If a method has been found of connecting a nerve ending in a brain directly with an electrical reactor, then the way is open for connecting it with a brain-cell of another person. Such a connection being, of course, essentially electrical, could be effected just as well through the ether as along wires. At first this would limit itself to the more perfect and economic transference of thought which would be necessary in the co-operative thinking of the future. But it cannot stop here. Connections between two or more minds would tend to become a more and more permanent condition until they functioned as a dual or multiple organism.

Finally, consciousness itself may end or vanish in a humanity that has become completely etherealize...