It all depends on the circumstances.

If you've crash-landed halfway between SoCal and Hawaii, the plane is sinking and you've got your mind and multi-tool, what are your chances of survival? I'd rather have a liferaft.

If you've just been rolled out of your own car trunk by carjackers and dumped way out in the Death Valley desert in January, just after dark, and the temperature is 20F, what's your plan? I would rather have firestarting tools and materials and an emergency blanket or tarp.

Your yacht just sank off a reef, and the highest point of the reef is a flat area about 1000 sqft, but it's all under a foot of water... what then? That liferaft is looking better and better.

If there's a way out, using your brain will help.

If there's nothing to use your multi-tool ON, you might as well not have it. Do you happen to have an abscessed tooth?

While there are conditions where a knife would be very useful, it isn't the be-all and end-all of survival.

A functioning brain and a more general kit that at least covers the basics (shelter, fire, water, signaling) is better than a brain and any single thing.

If I could only have one thing, FIRE would be my choice: I could keep myself warm if there was something to burn, I could boil water under some circumstances, I could signal for help.

A multi-tool: it can cut some things. Okay, go on from there.

Sue