Final answer:
Speculative suggests informed hypothesizing but not confirmed, whereas conjecture implies a more uncertain and less evidence-based guess. In terms of science, conjecture may be a starting point, which evolves into a hypothesis and eventually a theory through testing and confirmation.
Step-by-step explanation:
The difference between speculative and conjecture relates to the level of evidence and the context in which these terms are used. Speculative often suggests a level of hypothesizing that is informed by some evidence or logical reasoning, but not confirmed. For instance, speculative investments are understood to have a higher risk because they are based on potential future developments rather than guaranteed outcomes.
Conjecture, on the other hand, typically implies a guess that is more uncertain and less grounded in evidence. In the context of hypothesis formation in science, a conjecture can be seen as an early-stage hypothesis that has yet to be tested, whereas a hypothesis proceeds from conjecture to a more structured prediction that can be tested through experimental design.
When observing phenomena, scientists may begin with speculative ideas or conjectures, but through the scientific method, these evolve into hypotheses and with further testing and confirmation, potentially into theories.