Luis Rosa

Optical control of GIRK channels using visible light

G-protein coupled inwardly rectifying potassium (GIRK) channels are an integral part of inhibitory signal transduction pathways, reducing the activity of excitable cells via hyperpolarization. They play crucial roles in processes such as cardiac output, cognition and the coordination of movement. Therefore, the precision control of GIRK channels is of critical importance. Here, we describe the development of the azobenzene containing molecule VLOGO (Visible Light Operated GIRK channel Opener), which activates GIRK channels in the dark and is promptly deactivated when illuminated with green light. VLOGO is a valuable addition to the existing tools for the optical control of GIRK channels as it circumvents the need to use potentially harmful UV irradiation. We therefore believe that VLOGO will be a useful research tool for studying GIRK channels in biological systems.

Reasoning without regress

In this paper I explore alternative ways of answering the infinite regress problem of inference, as it was depicted in Lewis Carroll’s ‘What the Tortoise said to Achilles’. Roughly put, the problem is that if a claim to the effect that one’s premises give support to one’s conclusion must itself be part of one’s premises, then an infinite regress of reasons ensues. I discuss some recent attempts to solve that problem, but I find all of them to be wanting. Those attempts either require the reasoner to believe that her premises give support to her conclusion, or to take her premises to give support to her conclusion, where taking is not a doxastic attitude. I conclude that, on the face of the failure of those attempts to solve the problem, there is a strong prima facie case for allowing inference to be blind (in which case reasoners need not believe or take it that their premises give support to their conclusions).

Inferential basing and mental models

Abstract In this paper, I flesh out an account of the inferential basing relation using a theory about how humans reason: the mental models theory. I critically assess some of the notions that are used by that theory to account for inferential phenomena. To the extent that the mental models theory is well confirmed, that account of basing would be motivated on empirical grounds. This work illustrates how epistemologists could offer explications of the basing relation which are more detailed and less empirically risky.

ON THE PROBABILITY OF THEISM

The proposition expressed by ‘God exists’ (G), if it is true or false, is either necessarily true/false or not necessarily true/false. In other words, if G is capable of having a truth–value v, then it is either necessarily v or contingently v. By ‘God’ I mean a supernatural being, a powerful and immaterial mind that purportedly created the universe. Certainly there are other meanings that are attached to that term in certain contexts, but the arguments I will assess here only make sense under that interpretation.