Cells across the tree of life respond to a sudden, nonlethal rise in temperature--heat shock--in similar ways. Following heat shock, proteins and mRNAs form clumps, certain genes turn on, and protein synthesis and cell growth sharply decline. The standard interpretation of these long-studied phenomena has held that thermal energy causes proteins to misfold, forming toxic aggregates that require cleanup by the induced chaperone proteins. Substantial challenges to this misfolding-catastrophe interpretation have remained. A fundamentally different picture emerges from recent work: aggregation instead reflects evolved, adaptive biomolecular condensation processes integral to the sensation of and adaptation to temperature, and chaperones regulate these condensed states. I will discuss our ongoing molecular and cell-biological studies which have led to this alternative perspective in which temperature acts as a signal, rather than a proteotoxic stress.