- To make a false statement with the intention to deceive.
- To make an assertion that is believed to be false to some audience with the intention to deceive the audience about the content of that assertion.
Whether you consider a lie to be more or less morally wrong depends on your basis for morality. If you base it on an inviolable precept such as, "Thou shalt not bear false witness," you might find little leeway to consider the philosophical niceties. As I see it, the general prohibition on lying is to do with notions of trust and the reliability of communications. It may be perfectly moral to lie in certain specific circumstances (Jason suggested several), but if lying became the norm the fabric of society would quickly unravel.
Jason's second show was about time travel, and began with a discussion of definitions of time. Defining time appears to be fraught with impossibilities; for instance, what's the answer to the question, "How long can a condition of no change persist?" It depends whether you think time is something that passes, irrespective of events that occur. Note that of all our many ways of measuring time — to astonishing accuracy — none of them is objectively measuring the passage of time, but merely counting the occurrence of extremely regular events (although that raises the question of how we know these events are "regular").
However, this is pretty simple stuff in comparison with Jason's overview of alternative theories of time and his explanation of time-travel paradoxes — highly recommended, if you don't mind your brain turning to spaghetti.