T.Lo (invivoanalytics.com) talks about "commando trading", which really is the process of making decisions based on certain situations: if this breaks above a certain level, go long; or if it breaks below a support, go short; look for trade set-ups; bull/bear spreads, etc.
But it seems that no matter how disciplined, every trader has a certain bias for the overall market... a place from which to start, it's a must. If you really think the SPY is going to fall to aversion and the long bond is oversold, then why on earth would you waste time looking for long stock opportunities, except to hedge your net short positions?
If your basic thesis is wrong, you are going to have losses. Period. Sure, you can mitigate losses, but losses there will be. So this is the dilemma for all trading, and investing for that matter.