Temperature

I am fermenting a Belgian Tripel. The recipe says to ferment at around 60 degrees during the most vigorous stage, and then bring it up to 70 or so. I don't know the actual temperature inside the ale pale. But right now it is in my basement where the ambient temperature is a little below 60. Should I bring it upstairs at some point, where the ambient temperature is a little below 70? Or is the internal temp likely to get too high?

Also, why is the recipe having me do this? Is it because the yeast produces better flavors at lower temperatures, but will likely stall out at some point if the temperature does not go up?

If you started out at a higher temp, you might get too many yeast flavors. Raising the temp late does help the yeast finish, and will supposedly give you just the right amount of esters.

I don't think ambient ~68 is too high, especially given that it should be less violent inside, and thus won't be too much warmer than outside. I'd actually be concerned your initial fermentation in a room below 60 is too low.

It's probably 60. I just meant to emphasize that it isn't 65. If anything, a tad below rather than above. At any rate, it is fermenting really hard, so I don't think the temp is a problem at this point. Thanks!

Belgian yeasts typically like warmer temps. Most of the info that I have read says to pitch in the low to mid sixties and let free rise to 75 or even 80. For my belgians, I usually pitch at the same temp as most ales, low 60s, wrap the carboy in a towel and let is be in my living room, uncontrolled. Ambient is never more than 75 at its hottest over the summer, so it never gets too hot. I have done this with great success, YMMV.
In short, yes, if I were you, I'd bring it upstairs to the warmer temps.