- Halley's comet has a wanton tail
- handling editor
- hard core
- heavy bodies endeavour to reach the earth
- Helmholtz, Hermann von
- hermeneutics
- heuristic
- history conjecture
- Holden, Alan
- Hooke, Robert
- Hoyle, Fred
- Hume, David
- hybrid conception
- hydrogen bonds are like those you have with colleagues
- hypotheses may be hatched by theories of other species
- hypothesis-observation is like chicken-egg