What does it mean to be human?

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What does it mean to be a human? What is being? What is the difference between the being of humans and the being of non-humans?

These are all important and difficult to answer questions. Martin Heidegger was one philosopher who took it upon himself to attempt to answer some of these questions. His aim was to work out the general meaning of being and to do so concretely. Did he succeed? Some would say yes, others no. In this post, I’d like to sketch out a part of his answer, focusing on the the last question: the difference between the being of humans and the being of non-human animals i.e. the ontological difference.

The distinction between being and beings is there, latent in [humans] and [their] existence, even if not in explicit awareness. The distinction is there; that is to say, it has the mode of being of [humans]: it belongs to existence. Existence means, as it were, “to be in the performance of this distinction.” Only a soul that can make this distinction has the aptitude, going beyond the animal’s soul, to become the soul of a human being…we call the distinction between being and beings, when it is carried out explicitly, the ontological difference.

I’d like to concentrate on the part I made bold. This is crucial to his definition of what it means to be a human being[Dasein]. Essentially, humans comport themselves toward their own being. Another way of putting this awkward phrase is that humans take a stand on their own being. This is what “being in the performance of [the ontological difference]” means. Through the particular ways in which humans act within the world, we make this ontological difference a part of our existential mode of being. This means we always perceive/conceive and act in the world in terms of the difference between being and beings, between the the ontological being of ourselves and the entities which make up the physical world. There is something-it-is-like to be us, and that something has to do with how we already pre-ontologically make a distinction between being and beings.

Whether or not you think of all this is useless metaphysical mumbo-jumbo or an historical attempt to answer one of the most important questions in philosophy is up to you, but hopefully I made it clear that Heidegger was at least an original thinker.

edit: I have updated the original post to fix the inconsistencies pointed out by Roman.

UPDATE: What does it mean to be human: take two

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Thinking about Libet

In 1982, Benjamin Libet carried out a remarkable study on consciousness that is still being debated by contemporary philosophers and scientists. In today’s post I would like to briefly highlight the results and spell out some implications. Here are the most pertinent results as far as I can see them:

• In order to “consciously experience” a sensation, it must apparently bounce around the somatosensory cortex, or some other “high-level” area of the cortex for about half a second, probably isolated to the frontal areas(Libet, 1982)
• “A touch on the skin that the subjects would otherwise have reported feeling was retroactively masked up to half a second later by a stimulation to the cortex”(Blackmore, 2004)

Okay, so how can phenomenological consciousness “drag” half of a second behind the real world when clearly we are able to react much faster than that? The most obvious idea is to say that consciousness has no causal power, it is merely a resultant and not a force (in James’ terms). However, this is at odds with the “hard problem” of consciousness because if our “unconscious” does all the important work, such as reacting to dangerous stimuli in split-second situations, there would have been no evolutionary pressure for phenomenal consciousness to tag along and “dangle” half a second behind the real important things going on in the world, such as a stepping on a snake or braking for a red light.

I believe that I can sketch out a framework that can reasonably explain how consciousness could happen “after the fact”, yet still have enough function that it could easily have evolved in the way that it did given the close-knit social structures of our early hominid ancestors.

Let us look at Blackmore’s example of turning around to look who just opened a door while you are sitting in a classroom. This is what seems to happen:(from blackmore)

Scenario 1

1. Consciously hear sound
2. Turn around to look

According to Libet, it should be more like this:

Scenario 2

1. Unconsciously “hear” sound
2. Turn around to look
3. Backwards subjective referral of consciousness to make it seem like Scenario 1 is what actually happened

So how do we extricate ourselves from this mess? I think the first step is to recognize that you are setting up a false dichotomy of sorts by trying to directly reconcile scenarios 1 and 2 as the only two options. Furthermore, we should follow Dennett’s advice and use extreme conceptual caution when using the terms “conscious” and “unconscious”, because the nature of our language necessarily forces an implicit acceptance of the Cartesian Theater whenever we use the language of conscious/unconscious, and it is this intuitive dichotomy that makes it impossible to solve these kinds of philosophical problems using ordinary conceptual frameworks.

However, if we use the framework of enactive perception and attentional theories of consciousness, we will get a better understanding of why trying to decide between either Scenario 1 or 2 will only result in frustration and headaches. In my next post I will discuss an alternative way of looking at this problem. Stay tuned!

References
Libet, B. 1982 Brain Stimulation in the study of neuronal functions for conscious sensory experiences. Human Neurobiology 1, 235-42

Blackmore, S. 2004 Consciousness: An Introduction

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Consciousness and sleep

In this post, I want to discuss a paper entitled the “Breakdown of Cortical Effective Connectivity During Sleep”. In plain English, this paper discusses the theoretical possibility that consciousness fades during the night because the cortex essentially doesn’t talk to itself as much. More specifically, this study focused on NREM sleep, which accounts for roughly 75-80% of our total sleep time. During NREM sleep, people often report no dream experiences, and it is this lack conscious activity that the researchers wanted to investigate. What goes on in our brains during this period of non-consciousness?

In order to answer this question, the researchers used a combination of transcranial magnetic stimulation(TMS) and electroencephalography(EEG). Using TMS was advantageous for the researchers because they could stimulate the cortex directly without activating the subcortical reticular formation and the thalamo gating relay.

The researchers used TMS to stimulate the rostral portion of the right premotor cortex, which has dense connections with the rest of the cortex area, which is heavily correlated to typical wakeful consciousness. Now for the results:

During wakefulness, TMS induced a sustained response made of recurrent waves of activity…With the onset of NREM sleep, the brain response to TMS changed markedly. After [the initial] large wave, no further TMS-locked activity could be detected.
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Thus, during wakefulness, the perturbation of the rostral premotor cortex was followed by spatially and temporally differentiated patterns of activation that appeared to propagate along its anatomical connections. In striking contrast, during NREM sleep the location of maximum current density remained confined to the stimulated area.
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During wakefulness, the site of maximum activation moved back and forth among premotor and prefrontal areas in both hemispheres and, in some subjects, it also involved the motor and posterior parietal cortex. During NREM sleep, by contrast, the activity evoked by TMS did not propagate in space and time in any of the subjects.
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Thus, an impairment in the ability to integrate information among specialized thalamocortical modules—a proposed theoretical requirement for consciousness—may underlie the fading of consciousness in NREM sleep early in the night.

The researcher’s speculation on the potential neural mechanisms behind this decreased cortical activity during NREM sleep is a little beyond the scope of this blog, but it could have something to do with “down states” of depolarization being triggered more easily. Regardless,

Whatever the precise mechanisms, they are most likely engaged by the progressive reduction of the firing of diffuse neuromodulatory systems that occurs when we fall asleep.

For those interested, a good summary article of this research can be found here